Added checkout

Author: richardsimko

.github/workflows/update-major-version.yml

@@ -7,6 +7,8 @@ jobs:
     name: Update reference
     runs-on: ubuntu-latest
     steps:
+      - name: Checkout
+        uses: actions/checkout@v2
       - name: Extract major version from tag
         run: |
           FULL_VERSION=${GITHUB_REF##*/}