Merge pull request #11 from dchesterton/dependabot/github_actions/actions/checkout-2.3.4

Bump actions/checkout from 2 to 2.3.4

.github/workflows/publish.yml

@@ -12,7 +12,7 @@ jobs:
     runs-on: ubuntu-20.04
     steps:
       - name: Checkout code
-        uses: actions/checkout@v2
+        uses: actions/checkout@v2.3.4
       - name: Set up QEMU
         uses: docker/setup-qemu-action@v1
       - name: Set up Docker Buildx