fix: add variables for docker build

.builds-linux.goreleaser.yml

@@ -1,3 +1,15 @@
+env:
+  # Goreleaser always uses the docker buildx builder with name "default"; see
+  # https://github.com/goreleaser/goreleaser/pull/3199
+  # To use a builder other than "default", set this variable.
+  # Necessary for, e.g., GitHub actions cache integration.
+  - DOCKER_BUILDX_BUILDER={{ if index .Env "DOCKER_BUILDX_BUILDER"  }}{{ .Env.DOCKER_BUILDX_BUILDER }}{{ else }}default{{ end }}
+  # Setup to enable Docker to use, e.g., the GitHub actions cache; see
+  # https://docs.docker.com/build/building/cache/backends/
+  # https://github.com/moby/buildkit#export-cache
+  - DOCKER_BUILDX_CACHE_FROM={{ if index .Env "DOCKER_BUILDX_CACHE_FROM"  }}{{ .Env.DOCKER_BUILDX_CACHE_FROM }}{{ else }}type=registry{{ end }}
+  - DOCKER_BUILDX_CACHE_TO={{ if index .Env "DOCKER_BUILDX_CACHE_TO"  }}{{ .Env.DOCKER_BUILDX_CACHE_TO }}{{ else }}type=inline{{ end }}
+
 before:
   hooks:
     - go mod tidy