Update .gitlab-ci.yml file

.gitlab-ci.yml

@@ -1,6 +1,19 @@
-test:
 image: rust:1.59-alpine3.15
+
+stages:
+  - test
+
+test:
+  stage: test
   before_script:
     - apk --no-cache add musl-dev
   script:
     - cargo test
+
+audit:
+  stage: test
+  before_script:
+    - apk --no-cache add musl-dev
+    - cargo install cargo-audit
+  script:
+    - cargo audit