Merge branch 'buildah-cache' into 'main'

Use buildah cache

See merge request components/opentofu!165

.gitlab-ci.yml

@@ -139,6 +139,9 @@ gitlab-opentofu-image:build:
   script:
     - echo "Building $GITLAB_OPENTOFU_IMAGE_NAME"
     - buildah build
+      --layers
+      --cache-from $CI_REGISTRY_IMAGE/cache
+      --cache-to $CI_REGISTRY_IMAGE/cache
       --platform "$PLATFORMS"
       --build-arg OPENTOFU_VERSION=$OPENTOFU_VERSION
       --file Dockerfile.$GITLAB_OPENTOFU_BASE_IMAGE_OS