Log in to GHCR before pushing

Author: Skn0tt

.github/workflows/ci.yml

@@ -76,6 +76,12 @@ jobs:
     name: Push Docker image to GitHub Container Registry
     runs-on: ubuntu-latest
     steps:
+      - name: Login to GitHub Container Registry
+        uses: docker/login-action@v1
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
       - name: Docker meta
         id: meta
         uses: docker/metadata-action@v3