fix(ci): expose cached cargo-audit binary

.gitlab-ci.yml

@@ -57,6 +57,7 @@ security-audit:
       - .cargo/registry/index/
       - .cargo/registry/cache/
   before_script:
+    - export PATH="$CARGO_HOME/bin:$PATH"
     - command -v cargo-audit >/dev/null || cargo install cargo-audit --locked --version 0.22.2
   script:
     - cargo audit