fix: use lowercase image name and fix IMAGE_NAME references

Author: slchris

.github/workflows/build.yml

@@ -18,7 +18,6 @@ on:
 
 env:
   REGISTRY: ghcr.io
-  IMAGE_NAME: ${{ github.repository }}
   # Go version must match the requirement in Tailscale's go.mod
   GO_VERSION: '1.25'
 
@@ -105,6 +104,11 @@ jobs:
       - name: Checkout repository
         uses: actions/checkout@v4
 
+      - name: Set image name to lowercase
+        id: image
+        run: |
+          echo "name=${GITHUB_REPOSITORY,,}" >> $GITHUB_OUTPUT
+
       - name: Set up QEMU
         uses: docker/setup-qemu-action@v3
 
@@ -123,7 +127,7 @@ jobs:
         id: meta
         uses: docker/metadata-action@v5
         with:
-          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
+          images: ${{ env.REGISTRY }}/${{ steps.image.outputs.name }}
           tags: |
             type=ref,event=branch
             type=ref,event=pr
@@ -154,7 +158,7 @@ jobs:
         if: github.event_name != 'pull_request'
         uses: aquasecurity/trivy-action@master
         with:
-          image-ref: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:latest
+          image-ref: ${{ env.REGISTRY }}/${{ steps.image.outputs.name }}:latest
           format: 'sarif'
           output: 'trivy-results.sarif'
           severity: 'CRITICAL,HIGH'
@@ -163,7 +167,7 @@ jobs:
       - name: Build summary
         if: github.event_name != 'pull_request'
         run: |
-          echo "## Build Complete! 🎉" >> $GITHUB_STEP_SUMMARY
+          echo "## Build Complete!" >> $GITHUB_STEP_SUMMARY
           echo "" >> $GITHUB_STEP_SUMMARY
           echo "### Image Details" >> $GITHUB_STEP_SUMMARY
           echo "| Property | Value |" >> $GITHUB_STEP_SUMMARY
@@ -174,5 +178,5 @@ jobs:
           echo "" >> $GITHUB_STEP_SUMMARY
           echo "### Pull Command" >> $GITHUB_STEP_SUMMARY
           echo "\`\`\`bash" >> $GITHUB_STEP_SUMMARY
-          echo "docker pull ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:latest" >> $GITHUB_STEP_SUMMARY
+          echo "docker pull ${{ env.REGISTRY }}/${{ steps.image.outputs.name }}:latest" >> $GITHUB_STEP_SUMMARY
           echo "\`\`\`" >> $GITHUB_STEP_SUMMARY