ci: fix artifact upload

.github/workflows/docker.yaml

@@ -133,6 +133,12 @@ jobs:
             variant: php-${{ needs.prepare.outputs.php83_version }}-bookworm
             platform: linux/arm/v6
     steps:
+      -
+        name: Prepare
+        id: prepare
+        run: |
+          platform=${{ matrix.platform }}
+          echo "sanitized_platform=${platform//\//-}" >> "${GITHUB_OUTPUT}"
       -
         uses: actions/checkout@v4
         with:
@@ -200,7 +206,7 @@ jobs:
         if: fromJson(needs.prepare.outputs.push)
         uses: actions/upload-artifact@v4
         with:
-          name: metadata-builder-${{ matrix.variant }}-${{ matrix.platform }}
+          name: metadata-builder-${{ matrix.variant }}-${{ steps.prepare.outputs.sanitized_platform }}
           path: /tmp/metadata/builder/*
           if-no-files-found: error
           retention-days: 1
@@ -209,7 +215,7 @@ jobs:
         if: fromJson(needs.prepare.outputs.push)
         uses: actions/upload-artifact@v4
         with:
-          name: metadata-runner-${{ matrix.variant }}-${{ matrix.platform }}
+          name: metadata-runner-${{ matrix.variant }}-${{ steps.prepare.outputs.sanitized_platform }}
           path: /tmp/metadata/runner/*
           if-no-files-found: error
           retention-days: 1