feat: Add step to determine base branch for OpenAPI client regeneration

Author: YumNumm

.github/workflows/openapi-client.yaml

@@ -77,14 +77,21 @@ jobs:
           echo "has_changes=$has_changes"
           echo "has_changes=$has_changes" >> "$GITHUB_OUTPUT"
 
+      - name: Determine base branch
+        id: determine-base-branch
+        run: |
+          BASE_BRANCH="${{ github.event_name == 'pull_request' && github.event.pull_request.base.ref || github.event.repository.default_branch }}"
+          echo "base_branch=$BASE_BRANCH" >> "$GITHUB_OUTPUT"
+          echo "base_branch=$BASE_BRANCH"
+
       # https://github.com/peter-evans/create-pull-request
       - name: Create PR for regenerate OpenAPI client
         uses: peter-evans/create-pull-request@c0f553fe549906ede9cf27b5156039d195d2ece0 # v8.1.0
         if: steps.generate-openapi-client.outputs.has_changes == 'true'
         id: cpr
         with:
           token: ${{ steps.app-token.outputs.token }}
-          base: ${{ github.event_name == 'pull_request' && github.event.pull_request.base.ref || github.event.repository.default_branch }}
+          base: ${{ steps.determine-base-branch.outputs.base_branch }}
           delete-branch: true
           draft: true
           add-paths: "packages/eqmonitor_api/lib/**/*"