Rustfmt pass, and rustfmt --check in CI"

Signed-off-by: Maxime “pep” Buquet <pep@bouah.net>

.gitlab-ci.yml

@@ -1,4 +1,5 @@
 stages:
+  - lint
   - build
   - test
 
@@ -30,6 +31,11 @@ variables:
   script:
     - cargo test --verbose
 
+rustfmt:
+  stage: lint
+  script:
+    - rustfmt --check --edition 2018 **/*.rs
+
 rust-latest-build:
   extends:
     - .build