[v4/Breaking] Bump ubuntu: 22.04, minimum ruby: 2.5, minimum rails 5.0 (

#1128)

* ci: [v4/Breaking] bump ubuntu: 22.04, minimum ruby: 2.5, minimum rails 5.0

* ci: remove unused gemfiles

.github/workflows/ci.yml

@@ -8,7 +8,7 @@ on:
 
 jobs:
   build:
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-22.04
     strategy:
       matrix:
         ruby-version: [2.5.3, 2.6.0, 2.6.6, 2.7.2]
@@ -29,28 +29,6 @@ jobs:
             ruby-version: 3.0.3
           - gemfile: gemfiles/rails61.gemfile
             ruby-version: 3.0.3
-          - gemfile: gemfiles/rails42.gemfile
-            ruby-version: 2.4.5
-          - gemfile: gemfiles/rails42.gemfile
-            ruby-version: 2.3.8
-          - gemfile: gemfiles/rails42.gemfile
-            ruby-version: 2.2.10
-          - gemfile: gemfiles/rails41.gemfile
-            ruby-version: 2.3.0
-          - gemfile: gemfiles/rails41.gemfile
-            ruby-version: 2.2.10
-          - gemfile: gemfiles/rails41.gemfile
-            ruby-version: 2.1.9
-          - gemfile: gemfiles/rails40.gemfile
-            ruby-version: 2.3.0
-          - gemfile: gemfiles/rails40.gemfile
-            ruby-version: 2.2.10
-          - gemfile: gemfiles/rails40.gemfile
-            ruby-version: 2.1.9
-          - gemfile: gemfiles/rails32.gemfile
-            ruby-version: 2.2.10
-          - gemfile: gemfiles/rails32.gemfile
-            ruby-version: 2.1.9
 
     steps:
       - uses: actions/checkout@v2