fix: ensure lowercase-only letters in workflow

Former-commit-id: 2ffae68d1f22ff08eaddf829db3dccf1cf33988c
Former-commit-id: 3ba2583ac5a05a05669505db0f9171a1013b5e6d

.github/workflows/build.yaml

@@ -14,6 +14,11 @@ jobs:
         uses: actions/checkout@v4
         with:
           token: ${{ secrets.GITHUB_TOKEN }}
+      - id: convert-repository
+        name: Convert repository name to lowercase
+        uses: ASzc/change-string-case-action@v6
+        with:
+          string: ${{ github.repository }}
       - name: Set up QEMU
         uses: docker/setup-qemu-action@v3
       - name: Set up Docker Buildx
@@ -26,4 +31,4 @@ jobs:
           password: ${{ secrets.GITHUB_TOKEN }}
       - name: Build and push
         run: |
-          docker buildx build -f Dockerfile . --tag ghcr.io/${{ github.actor }}/arma-3-artillery-calculator:latest --platform linux/amd64,linux/arm64 --push
+          docker buildx build -f Dockerfile . --tag ghcr.io/${{ steps.convert-repository.outputs.lowercase }}:latest --platform linux/amd64,linux/arm64 --push