Fix Update Package Versions step: use bash instead of CMD

The CMD approach failed because:
1. wmic is deprecated and not available on the Windows runner
2. PowerShell pipes inside CMD were misinterpreted

Switch to bash which is now available on the Windows runner.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

.gitea/workflows/release.yml

@@ -131,30 +131,25 @@ jobs:
           echo Definitions and docs packaged
 
       - name: Update Package Versions
-        shell: cmd
+        shell: bash
         run: |
-          setlocal enabledelayedexpansion
+          VERSION="$CLEAN_VERSION"
+          CHANNEL="$CHANNEL"
+          TODAY=$(date +%Y-%m-%d)
 
-          set "VERSION=%CLEAN_VERSION%"
-          set "CHANNEL=%CHANNEL%"
+          echo "Updating to version $VERSION for channel $CHANNEL on $TODAY"
 
-          REM Get today's date in YYYY-MM-DD format
-          for /f "tokens=2 delims==" %%I in ('wmic os get localdatetime /value') do set "DT=%%I"
-          set "TODAY=!DT:~0,4!-!DT:~4,2!-!DT:~6,2!"
+          # Update package.xml files
+          find installer/packages -name "package.xml" | while read f; do
+            sed -i "s|<Version>.*</Version>|<Version>$VERSION</Version>|g" "$f"
+            sed -i "s|<ReleaseDate>.*</ReleaseDate>|<ReleaseDate>$TODAY</ReleaseDate>|g" "$f"
+          done
 
-          echo Updating to version !VERSION! for channel !CHANNEL! on !TODAY!
+          # Update config.xml
+          sed -i "s|<Version>.*</Version>|<Version>$VERSION</Version>|g" installer/config/config.xml
+          sed -i "s|repository/[^<\"]*|repository/$CHANNEL|g" installer/config/config.xml
 
-          REM Update package.xml files using PowerShell for regex
-          for /r installer\packages %%f in (package.xml) do (
-            if exist "%%f" (
-              powershell -Command "(Get-Content '%%f') -replace '<Version>.*</Version>', '<Version>%VERSION%</Version>' -replace '<ReleaseDate>.*</ReleaseDate>', '<ReleaseDate>%TODAY%</ReleaseDate>' | Set-Content '%%f'"
-            )
-          )
-
-          REM Update config.xml
-          powershell -Command "(Get-Content 'installer\config\config.xml') -replace '<Version>.*</Version>', '<Version>%VERSION%</Version>' -replace 'repository/[^<\"]*', 'repository/%CHANNEL%' | Set-Content 'installer\config\config.xml'"
-
-          echo Updated versions to !VERSION! for channel !CHANNEL!
+          echo "Updated versions to $VERSION for channel $CHANNEL"
 
       - name: Generate Repository
         shell: cmd