ci: Make able to run workflow in forks with uppercase in names (#782)

### Description of your changes

Deal with

```
ERROR: invalid tag "ghcr.io/MaxymVlasov/pre-commit-terraform-712:latest": repository name must be lowercase
```

Found during testing changes for OSSF score improvement - as I need to test all workflows without disrupting main repo 

---------

Co-authored-by: George L. Yermulnik <[email protected]>

Author: MaxymVlasov

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

@@ -32,6 +32,12 @@ jobs:
           .github/workflows/build-image-test.yaml
           tools/*.sh
 
+    - name: Set IMAGE environment variable
+      # Lowercase the org/repo name to allow for workflow to run in forks,
+      # which owners have uppercase letters in username
+      run: >-
+        echo "IMAGE=ghcr.io/${GITHUB_REPOSITORY@L}:${{ env.IMAGE_TAG }}"
+        >> $GITHUB_ENV
     - name: Set up QEMU
       if: matrix.os != 'ubuntu-latest' || matrix.arch != 'amd64'
       # yamllint disable-line rule:line-length
@@ -56,8 +62,7 @@ jobs:
           linux/${{ matrix.arch }}
         push: false
         load: true
-        tags: |
-          ghcr.io/${{ github.repository }}:${{ env.IMAGE_TAG }}
+        tags: ${{ env.IMAGE }}
         # Fix multi-platform: https://github.com/docker/buildx/issues/1533
         provenance: false
         secrets: |
@@ -68,15 +73,15 @@ jobs:
       # yamllint disable-line rule:line-length
       uses: plexsystems/container-structure-test-action@c0a028aa96e8e82ae35be556040340cbb3e280ca  # v0.3.0
       with:
-        image: ghcr.io/${{ github.repository }}:${{ env.IMAGE_TAG }}
+        image: ${{ env.IMAGE }}
         config: .github/.container-structure-test-config.yaml
 
     - name: Dive - check image for waste files
       if: steps.changed-files-specific.outputs.any_changed == 'true'
       # yamllint disable-line rule:line-length
       uses: MaxymVlasov/dive-action@379af3fc636888ada5899c997e8b52db6ad45023  # v1.0.1
       with:
-        image: ghcr.io/${{ github.repository }}:${{ env.IMAGE_TAG }}
+        image: ${{ env.IMAGE }}
         config-file: ${{ github.workspace }}/.github/.dive-ci.yaml
         github-token: ${{ secrets.GITHUB_TOKEN }}
 
@@ -95,8 +100,7 @@ jobs:
           INSTALL_ALL=true
         platforms: linux/amd64,linux/arm64
         push: false
-        tags: |
-          ghcr.io/${{ github.repository }}:${{ env.IMAGE_TAG }}
+        tags: ${{ env.IMAGE }}
         # Fix multi-platform: https://github.com/docker/buildx/issues/1533
         provenance: false
         secrets: |

.github/workflows/build-image.yaml

@@ -37,6 +37,11 @@ jobs:
         || echo 'latest'
         ) >> $GITHUB_ENV
 
+    - name: Set IMAGE_REPO environment variable
+      # 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@L}" >> $GITHUB_ENV
     - name: Set up Docker Buildx
       # yamllint disable-line rule:line-length
       uses: docker/setup-buildx-action@6524bf65af31da8d45b59e8c27de4bd072b392f5  # v3.8.0
@@ -52,8 +57,8 @@ jobs:
         platforms: linux/amd64,linux/arm64
         push: true
         tags: |
-          ghcr.io/${{ github.repository }}:${{ env.IMAGE_TAG }}
-          ghcr.io/${{ github.repository }}:latest
+          ${{ env.IMAGE_REPO }}:${{ env.IMAGE_TAG }}
+          ${{ env.IMAGE_REPO }}:latest
         # Fix multi-platform: https://github.com/docker/buildx/issues/1533
         provenance: false
         secrets: |
@@ -70,7 +75,7 @@ jobs:
         platforms: linux/amd64,linux/arm64
         push: true
         tags: |
-          ghcr.io/${{ github.repository }}:nightly
+          ${{ env.IMAGE_REPO }}:nightly
         # Fix multi-platform: https://github.com/docker/buildx/issues/1533
         provenance: false
         secrets: |