fix(): use github example for matrix build

Author: Podginator

.github/workflows/build-self-host-docker-images.yml

@@ -151,8 +151,8 @@ jobs:
           labels: ${{ steps.meta.outputs.labels }}
           tags: ${{ env.WEB_IMAGE }}
           outputs: type=image,push-by-digest=true,name-canonical=true,push=true
-          cache-from: type=registry,ref=ghcr.io/omnivore-app/sh-web:cache-${{matrix.platform}}
-          cache-to: type=registry,ref=ghcr.io/omnivore-app/sh-web:cache-${{matrix.platform}},mode=max
+          cache-from: type=registry,ref=ghcr.io/omnivore-app/sh-web-${{matrix.platform}}:cache
+          cache-to: type=registry,ref=ghcr.io/omnivore-app/sh-web-${{matrix.platform}}:cache,mode=max
       - name: Export digest
         run: |
           mkdir -p ${{ runner.temp }}/digests