ci: Add scope parameter to cache-{to,from} options

This change fixes an issue where only the latest image cache was
available.

.github/actions/run-in-docker-action/action.yml

@@ -7,6 +7,10 @@ inputs:
   tag:
     description: 'A tag of an image'
     required: true
+  scope:
+    description: 'A cached image scope'
+    required: false
+    default: ${{ runner.arch }}
   command:
     description: 'A command to run in a container'
     required: false
@@ -24,7 +28,7 @@ runs:
         file: ${{ inputs.dockerfile }}
         tags: ${{ inputs.tag }}
         load: true
-        cache-from: type=gha
+        cache-from: type=gha,scope=${{ inputs.scope }}
 
     - uses: docker/build-push-action@v5
       id: retry_builder
@@ -34,7 +38,7 @@ runs:
         file: ${{ inputs.dockerfile }}
         tags: ${{ inputs.tag }}
         load: true
-        cache-from: type=gha
+        cache-from: type=gha,scope=${{ inputs.scope }}
 
     - # Workaround for https://github.com/google/sanitizers/issues/1614 .
       # The underlying issue has been fixed in clang 18.1.3.

.github/workflows/ci.yml

@@ -71,8 +71,8 @@ jobs:
         with:
           file: ./ci/linux-debian.Dockerfile
           tags: ${{ matrix.arch }}-debian-image
-          cache-from: type=gha
+          cache-from: type=gha,scope=${{ runner.arch }}
-          cache-to: type=gha,mode=min
+          cache-to: type=gha,scope=${{ runner.arch }},mode=min
 
   x86_64-debian:
     name: "x86_64: Linux (Debian stable)"