fix lowercase image name in workflow

.github/workflows/deploy.yml

@@ -6,8 +6,6 @@ on:
 
 env:
   REGISTRY: ghcr.io
-  BACKEND_IMAGE: ghcr.io/${{ github.repository_owner }}/petshop-backend
-  FRONTEND_IMAGE: ghcr.io/${{ github.repository_owner }}/petshop-web
 
 jobs:
   build-and-deploy:
@@ -20,6 +18,12 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v4
 
+      - name: Set image names (lowercase)
+        run: |
+          OWNER=$(echo "${{ github.repository_owner }}" | tr '[:upper:]' '[:lower:]')
+          echo "BACKEND_IMAGE=ghcr.io/${OWNER}/petshop-backend" >> $GITHUB_ENV
+          echo "FRONTEND_IMAGE=ghcr.io/${OWNER}/petshop-web" >> $GITHUB_ENV
+
       - name: Log in to GitHub Container Registry
         uses: docker/login-action@v3
         with: