Add cargo-audit to CI (#40)

.github/workflows/main.yml

@@ -7,6 +7,28 @@ on:
     types: [opened, repoened, synchronize]
 
 jobs:
+  cargo-audit:
+    name: Audit
+    runs-on: ubuntu-latest
+    steps:
+      - name: Cache cargo-audit
+        uses: actions/cache@v2
+        with:
+          path: |
+            ~/.cargo/.crates.toml
+            ~/.cargo/.crates2.json
+            ~/.cargo/bin/cargo-audit
+          key: cargo-audit
+
+      - name: Install cargo-audit
+        run: cargo install cargo-audit
+
+      - name: Checkout sources
+        uses: actions/checkout@v2
+
+      - name: Run cargo audit
+        run: cargo audit -D warnings
+
   test:
     runs-on: ubuntu-latest
     strategy: