fix(ci): use GITHUB_SHA for workflow_dispatch (manual) events

.github/actions/prepare/action.yml

@@ -10,7 +10,7 @@ runs:
       run: |
         echo "LAST_COMMIT_SHA=${{ github.event.pull_request.head.sha }}" >> ${GITHUB_ENV}
     - name: Setup Environment (Push)
-      if: ${{ github.event_name == 'push' }}
+      if: ${{ github.event_name == 'push' || github.event_name == 'workflow_dispatch' }}
       shell: bash
       run: |
         echo "LAST_COMMIT_SHA=${GITHUB_SHA}" >> ${GITHUB_ENV}