refactor: remove push from cache-from and cache-to

`push` has no meaning in the context of `cache-from` or `cache-to`.

PR: #20

.github/workflows/containers.yml

@@ -23,10 +23,8 @@ jobs:
         include:
           - target: dev
             cache-to: dev
-            push-cache: true
           - target: build
             cache-to: build
-            push-cache: false
     steps:
       - name: Login to GitHub Container Registry
         uses: docker/login-action@v1
@@ -87,8 +85,8 @@ jobs:
             org.opencontainers.image.source=${{ github.server_url }}/${{ github.repository }}
           tags: |
             docker.io/${{ secrets.DOCKER_HUB_NAMESPACE }}/${{ steps.vars.outputs.candidate-tag }}
-          cache-from: type=registry,ref=docker.io/${{ secrets.DOCKER_HUB_NAMESPACE }}/${{ steps.vars.outputs.cache-from }},push=false
-          cache-to: type=registry,ref=docker.io/${{ secrets.DOCKER_HUB_NAMESPACE }}/${{ steps.vars.outputs.cache-to }},mode=max,push=${{ matrix.push-cache }}
+          cache-from: type=registry,ref=docker.io/${{ secrets.DOCKER_HUB_NAMESPACE }}/${{ steps.vars.outputs.cache-from }}
+          cache-to: type=registry,ref=docker.io/${{ secrets.DOCKER_HUB_NAMESPACE }}/${{ steps.vars.outputs.cache-to }},mode=max
           push: true
       - name: Image digest
         if: ${{ !startsWith(github.ref, 'refs/tags') }}