chore: Migrate from Python to .NET for release progress reporting

.config/dotnet-tools.json

@@ -0,0 +1,12 @@
+{
+  "version": 1,
+  "isRoot": true,
+  "tools": {
+    "Google.Cloud.Tools.ReleaseProgressReporter": {
+      "version": "0.3.0",
+      "commands": [
+        "release-progress-reporter"
+      ]
+    }
+  }
+}

.kokoro/autorelease.sh

@@ -7,31 +7,13 @@ SCRIPT_DIR=$(dirname "$SCRIPT")
 
 cd $SCRIPT_DIR
 
-# Make sure secrets are loaded in a well known localtion before running releasetool
+# Make sure secrets are loaded in a well known location before running
+# the release reporter script.
 source ./populatesecrets.sh
 populate_all_secrets
 
-# Make sure we have the most recent version of pip, then install other packages.
-python -m pip install --require-hashes -r pip-requirements.txt
-python -m pip install --require-hashes -r requirements.txt
-python -m releasetool publish-reporter-script > /tmp/publisher-script
-
-# The publish reporter script uses "python3" which doesn't exist on Windows.
-# Work out what we should use instead.
-# Try to detect Python 3. It's quite different between Windows and Linux.
-if which python > /dev/null && python --version 2>&1 | grep -q "Python 3"; then declare -r PYTHON3=python
-elif which py > /dev/null && py -3 --version 2>&1 | grep -q "Python 3"; then declare -r PYTHON3="py -3"
-elif which python3 > /dev/null && python3 --version 2>&1 | grep -q "Python 3"; then declare -r PYTHON3=python3
-else
-  echo "Unable to detect Python 3 installation."
-  exit 1
-fi
-
-# Fix up the publish reporter script using $PYTHON3. We assume this won't
-# be harmful within sed - at the moment it's always "python", "py -3" or "python3".
-sed -i "s/python3/$PYTHON3/g" /tmp/publisher-script
-
-source /tmp/publisher-script
+dotnet tool restore
+source <(dotnet release-progress-reporter publish-reporter-script)
 
 # Secrets are already populated, let's not do that again
 ./release.sh --skippopulatesecrets