fix: isolate base image merge artifacts (#79)

The merge jobs filtered artifacts by a prefix that let alpine also download alpine-docker digests. Use an unambiguous artifact name separator so each merge job only assembles manifests from its own image digests.

Author: lox

.github/workflows/base-image.yml

@@ -65,7 +65,7 @@ jobs:
 
       - uses: actions/upload-artifact@v4
         with:
-          name: digests-${{ env.IMAGE_NAME }}-${{ matrix.platform_key }}
+          name: digests__${{ env.IMAGE_NAME }}__${{ matrix.platform_key }}
           path: ${{ runner.temp }}/digests/*
           if-no-files-found: error
           retention-days: 1
@@ -88,7 +88,7 @@ jobs:
 
       - uses: actions/download-artifact@v4
         with:
-          pattern: digests-${{ env.IMAGE_NAME }}-*
+          pattern: digests__${{ env.IMAGE_NAME }}__*
           path: ${{ runner.temp }}/digests
           merge-multiple: true
 
@@ -174,7 +174,7 @@ jobs:
 
       - uses: actions/upload-artifact@v4
         with:
-          name: digests-${{ env.IMAGE_NAME }}-${{ matrix.platform_key }}
+          name: digests__${{ env.IMAGE_NAME }}__${{ matrix.platform_key }}
           path: ${{ runner.temp }}/digests/*
           if-no-files-found: error
           retention-days: 1
@@ -197,7 +197,7 @@ jobs:
 
       - uses: actions/download-artifact@v4
         with:
-          pattern: digests-${{ env.IMAGE_NAME }}-*
+          pattern: digests__${{ env.IMAGE_NAME }}__*
           path: ${{ runner.temp }}/digests
           merge-multiple: true
 
@@ -283,7 +283,7 @@ jobs:
 
       - uses: actions/upload-artifact@v4
         with:
-          name: digests-${{ env.IMAGE_NAME }}-${{ matrix.platform_key }}
+          name: digests__${{ env.IMAGE_NAME }}__${{ matrix.platform_key }}
           path: ${{ runner.temp }}/digests/*
           if-no-files-found: error
           retention-days: 1
@@ -306,7 +306,7 @@ jobs:
 
       - uses: actions/download-artifact@v4
         with:
-          pattern: digests-${{ env.IMAGE_NAME }}-*
+          pattern: digests__${{ env.IMAGE_NAME }}__*
           path: ${{ runner.temp }}/digests
           merge-multiple: true