Merge branch 'fixci' into 'master'

Use an Arch Linux container for CI

See merge request archlinux/rebuilder!1

.gitlab-ci.yml

-image: "rust:latest"
+image: "archlinux:latest"
 
-test:cargo:
+before_script:
+  - pacman -Syu --needed --noconfirm rust gcc
+
+stages:
+  - format
+  - clippy
+  - check
+
+format:
+  stage: format
+  script:
+    - cargo fmt --all -- --check
+
+clippy:
+  stage: clippy
+  script:
+    - cargo clippy --all -- -D warnings
+
+check:
+  stage: check
   script:
-    - cargo test --all
\ No newline at end of file
+    - cargo check --all --verbose --release