Apply suggestions from code review

Author: MaxymVlasov

.github/workflows/build-image-test.yaml

@@ -37,7 +37,7 @@ jobs:
       # which owners have uppercase letters in username
       shell: bash
       run: >-
-        echo "IMAGE=ghcr.io/${GITHUB_REPOSITORY,,}:${{ env.IMAGE_TAG }}"
+        echo "IMAGE=ghcr.io/${${{ github.repository }}@L}:${{ env.IMAGE_TAG }}"
           >> $GITHUB_ENV
 
     - name: Set up QEMU

.github/workflows/build-image.yaml

@@ -42,7 +42,7 @@ jobs:
       # Lowercase the org/repo name to allow for workflow to run in forks,
       # which owners have uppercase letters in username
       run: >-
-        echo "IMAGE_REPO=ghcr.io/:${GITHUB_REPOSITORY,,}"
+        echo "IMAGE_REPO=ghcr.io/:${${{ github.repository }}@L}"
           >> $GITHUB_ENV
 
     - name: Set up Docker Buildx