Update Freedesktop Metainfo (SuperTux#2684)

* Metainfo file: Use reverse DNS ID and .metainfo.xml extension

https://www.freedesktop.org/software/appstream/docs/chap-Metadata.html#spec-component-location

* Metainfo: Use 'GPL-3.0-or-later' in <project_license> tag instead of 'GPL-3.0-or-later AND CC-BY-SA-2.0' as recommended by the Freedesktop specification

https://www.freedesktop.org/software/appstream/docs/chap-Metadata.html#tag-project_license

* Metainfo: Change <developer_name/> tag to <developer/>

https://www.freedesktop.org/software/appstream/docs/chap-Metadata.html#tag-developer

* Metainfo: Add more <url/> tags

* Metainfo: Extend description

* Metainfo: Update screenshot selection and add captions

P: org.supertuxproject.SuperTux:3: cid-contains-uppercase-letter
     org.supertuxproject.SuperTux
   The component ID should only contain lowercase characters.

? Validation was successful: pedantic: 1

makedist.sh

@@ -12,7 +12,7 @@ fi
 echo "Creating directory $DISTDIR"
 mkdir "$DISTDIR" || exit 1
 
-cp "CMakeLists.txt" "LICENSE.txt" "INSTALL.md" "README.md" "NEWS.md" "config.h.cmake" "makedist.sh" "makepot.sh" "supertux2.appdata.xml" "supertux2.desktop" "version.cmake" "version.cmake.in" "version.h.in" $DISTDIR
+cp "CMakeLists.txt" "LICENSE.txt" "INSTALL.md" "README.md" "NEWS.md" "config.h.cmake" "makedist.sh" "makepot.sh" "org.supertuxproject.SuperTux.metainfo.xml" "supertux2.desktop" "version.cmake" "version.cmake.in" "version.h.in" $DISTDIR
 cp --parents mk/cmake/*.cmake $DISTDIR
 cp --parents mk/msvc/* $DISTDIR
 

mk/cmake/SuperTux/BuildInstall.cmake

@@ -64,7 +64,7 @@ install(FILES ${CMAKE_CURRENT_SOURCE_DIR}/INSTALL.md ${CMAKE_CURRENT_SOURCE_DIR}
 
 install(FILES ${CMAKE_CURRENT_SOURCE_DIR}/data/credits.stxt DESTINATION ${INSTALL_SUBDIR_SHARE})
 
-install(FILES ${CMAKE_CURRENT_SOURCE_DIR}/supertux2.appdata.xml DESTINATION "share/metainfo" )
+install(FILES ${CMAKE_CURRENT_SOURCE_DIR}/org.supertuxproject.SuperTux.metainfo.xml DESTINATION "share/metainfo" )
 
 install(DIRECTORY
   ${CMAKE_CURRENT_SOURCE_DIR}/data/images

org.supertuxproject.SuperTux.metainfo.xml

@@ -0,0 +1,93 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<component type="desktop-application">
+  <id>org.supertuxproject.SuperTux</id>
+  <metadata_license>CC0-1.0</metadata_license>
+  <project_license>GPL-3.0-or-later</project_license>
+  <content_rating type="oars-1.1">
+    <content_attribute id="violence-cartoon">mild</content_attribute>
+    <content_attribute id="language-humor">mild</content_attribute>
+  </content_rating>
+  <name>SuperTux</name>
+  <summary>A jump-and-run game starring Tux the Penguin</summary>
+  <description>
+    <p>
+      Run and jump through multiple worlds, fight off enemies by
+      jumping on them, bumping them from below or tossing objects at
+      them, grabbing power-ups and other stuff on the way.
+    </p>
+    <p>
+      In addition to the Story Mode, there is a large amount of
+      community contributed levels available as add-ons or in the
+      forums. Everyone can contribute such content by using the
+      integrated level editor.
+    </p>
+    <p>
+      The Story: Penny Gets Captured!
+    </p>
+    <p>
+      Tux and Penny were out having a nice picnic on the ice fields
+      of Antarctica. Suddenly, everything was a blur as Tux was
+      knocked out!
+    </p>
+    <p>
+      When Tux wakes up, he finds that Penny is missing. Where she
+      lay before now lies a letter. “Tux, my arch enemy!” says the
+      letter. “I have captured your beautiful Penny and have taken
+      her to my fortress. The path to my fortress is littered with
+      my minions. Give up on the thought of trying to reclaim her,
+      you haven’t got a chance! -Nolok”
+    </p>
+    <p>
+      Tux looks and sees Nolok’s fortress in the distance.
+      Determined to save his beloved Penny, he begins his journey
+      through the Icy Island and beyond.
+    </p>
+  </description>
+  <developer id="supertuxproject.org">
+    <name>The SuperTux Team</name>
+  </developer>
+  <url type="homepage">https://www.supertux.org</url>
+  <url type="bugtracker">https://github.com/SuperTux/supertux/issues</url>
+  <url type="faq">https://github.com/SuperTux/supertux/wiki/SuperTux_FAQ</url>
+  <url type="help">https://github.com/SuperTux/supertux/wiki/User-Manual</url>
+  <url type="donation">https://www.supertux.org/donate.html</url>
+  <url type="translate">https://github.com/SuperTux/supertux/wiki/Translation</url>
+  <url type="contact">https://github.com/SuperTux/supertux#community</url>
+  <url type="vcs-browser">https://github.com/SuperTux/supertux</url>
+  <url type="contribute">https://github.com/SuperTux/supertux/blob/master/CONTRIBUTING.md</url>
+  <categories>
+    <category>Game</category>
+    <category>ActionGame</category>
+    <category>ArcadeGame</category>
+  </categories>
+  <screenshots>
+    <screenshot type="default">
+      <image>https://www.supertux.org/images/0_6_0/0_6_0_3.png</image>
+      <caption>An Icy Island level</caption>
+    </screenshot>
+    <screenshot>
+      <image>https://www.supertux.org/images/0_6_0/0_6_0_2.png</image>
+      <caption>The Icy Island world map</caption>
+    </screenshot>
+    <screenshot>
+      <image>https://www.supertux.org/images/0_6_0/0_6_0_4.png</image>
+      <caption>Another Icy Island level</caption>
+    </screenshot>
+    <screenshot>
+      <image>https://www.supertux.org/images/0_6_0/0_6_0_14.png</image>
+      <caption>A Rooted Forest level</caption>
+    </screenshot>
+  </screenshots>
+  <launchable type="desktop-id">supertux2.desktop</launchable>
+  <provides>
+    <binary>supertux2</binary>
+  </provides>
+  <releases>
+    <release version="0.6.3" date="2021-12-22" />
+    <release version="0.6.2" date="2020-05-14" />
+    <release version="0.6.1.1" date="2019-12-19" />
+    <release version="0.6.1" date="2019-12-15" />
+    <release version="0.6.0" date="2018-12-23" />
+    <release version="0.5.1" date="2016-11-05" />
+  </releases>
+</component>