CI: fix release pr target (#90999)

* use inputs.target as checkout ref, and `main` for all reused actions.

.github/workflows/changelog.yml

@@ -62,6 +62,7 @@ jobs:
       - name: "Checkout Grafana repo"
         uses: "actions/checkout@v4"
         with:
+          ref: main
           sparse-checkout: |
             .github/workflows
             CHANGELOG.md
@@ -123,7 +124,7 @@ jobs:
             --label "no-backport" \
             --label "no-changelog" \
             -B "${{ inputs.target }}" \
-            --title "Release: ${{ inputs.version }}" \
+            --title "Release: update changelog for ${{ inputs.version }}" \
             --body "Changelog changes for release ${{ inputs.version }}"
         env:
           GH_TOKEN: ${{ steps.generate_token.outputs.token }}

.github/workflows/release-pr.yml

@@ -59,9 +59,16 @@ jobs:
       - name: Checkout Grafana
         uses: actions/checkout@v4
         with:
+          ref: ${{ inputs.target }}
           fetch-depth: 0
           fetch-tags: true
-
+      - name: Checkout Grafana (main)
+        uses: actions/checkout@v4
+        with:
+          ref: km/fix-release-pr-target
+          fetch-depth: '0'
+          fetch-tags: 'false'
+          path: .grafana-main
       - name: Configure git user
         run: |
           git config --local user.name "github-actions[bot]"
@@ -70,15 +77,13 @@ jobs:
 
       - name: Create branch
         run: git checkout -b "release/${{ github.run_id }}/${{ inputs.version }}"
-
       - name: Generate changelog
         id: changelog
-        uses: ./.github/workflows/actions/changelog
+        uses: ./.grafana-main/.github/workflows/actions/changelog
         with:
           github_token: ${{ steps.generate_token.outputs.token }}
           target: v${{ inputs.version }}
           output_file: changelog_items.md
-
       - name: Patch CHANGELOG.md
         run: |
           # Prepare CHANGELOG.md content with version delimiters
@@ -112,16 +117,16 @@ jobs:
           git diff CHANGELOG.md
 
       - name: Commit CHANGELOG.md changes
-        run: git commit --allow-empty -m "Update changelog placeholder" CHANGELOG.md
+        run: git add CHANGELOG.md && git commit --allow-empty -m "Update changelog" CHANGELOG.md
 
       - name: Update package.json versions
-        uses: ./pkg/build/actions/bump-version
+        uses: ./.grafana-main/pkg/build/actions/bump-version
         with:
-          version: ${{ inputs.version }}
+          version: 'patch'
 
       - name: Add package.json changes
         run: |
-          git add .
+          git add package.json lerna.json yarn.lock packages public
           git commit -m "Update version to ${{ inputs.version }}"
 
       - name: Git push
@@ -133,6 +138,7 @@ jobs:
         run: >
           gh pr create \
             $( [ "x${{ inputs.latest }}" == "xtrue" ] && printf %s '-l "release/latest"') \
+            -l "no-changelog" \
             --dry-run=${{ inputs.dry_run }} \
             -B "${{ inputs.target }}" \
             --title "Release: ${{ inputs.version }}" \
@@ -146,6 +152,7 @@ jobs:
           gh pr create \
             $( [ "x${{ inputs.latest }}" == "xtrue" ] && printf %s '-l "release/latest"') \
             -l "product-approved" \
+            -l "no-changelog" \
             --dry-run=${{ inputs.dry_run }} \
             -B "${{ inputs.target }}" \
             --title "Release: ${{ inputs.version }}" \