Gitlab CI: Additional stages

.gitlab-ci.yml

 stages:
-  - lint
+  - format
   - build
+  - lint
   - test
+  - image
 
 .rust_template: &rust_template
   cache:
@@ -30,28 +32,24 @@ rust-nightly-test:
     - cargo test --verbose
 
 rust-nightly-fmt:
-  stage: lint
+  stage: format
   image: rustlang/rust:nightly
   <<: *rust_template
   script:
     - cargo fmt --all --verbose -- --check
 
 rust-nightly-clippy:
-  stage: build
+  stage: lint
   image: rustlang/rust:nightly
-  needs:
-    - rust-nightly
   <<: *rust_template
   script:
     - cargo clippy --all --verbose -- -D warnings
 
 rust-nightly-docker:
-  stage: build
+  stage: image
   image:
     name: gcr.io/kaniko-project/executor:debug
     entrypoint: [""]
-  needs:
-    - rust-nightly
   script:
     - mkdir -p /kaniko/.docker
     - echo "{\"auths\":{\"$CI_REGISTRY\":{\"username\":\"$CI_REGISTRY_USER\",\"password\":\"$CI_REGISTRY_PASSWORD\"}}}" > /kaniko/.docker/config.json