Make merge conditional on milestone

Author: artembilan

.github/workflows/spring-merge-dependabot-pr.yml

@@ -50,6 +50,7 @@ jobs:
           gh pr edit ${{ github.event.pull_request.number }} --remove-label "${{ inputs.dependenciesLabel }}"
 
       - name: Set Milestone to Dependabot pull request
+        id: set-milestone
         run: |
           if test -f pom.xml
           then
@@ -60,7 +61,15 @@ jobs:
           export CANDIDATE_VERSION=${CURRENT_VERSION/-SNAPSHOT}
           MILESTONE=$(gh api repos/$GITHUB_REPOSITORY/milestones --jq 'map(select(.due_on != null and (.title | startswith(env.CANDIDATE_VERSION)))) | .[0] | .title')
           
-          gh pr edit ${{ github.event.pull_request.number }} --milestone $MILESTONE
+          if [ -z $MILESTONE ]
+          then
+            gh run cancel ${{ github.run_id }}
+            echo "::warning title=Cannot merge::No scheduled milestone for $CURRENT_VERSION version"
+          else
+            gh pr edit ${{ github.event.pull_request.number }} --milestone $MILESTONE
+            echo mergeEnabled=true >> $GITHUB_OUTPUT
+          fi
 
       - name: Merge Dependabot pull request
+        if: steps.set-milestone.outputs.mergeEnabled
         run: gh pr merge ${{ github.event.pull_request.number }} --auto --squash --rebase