style(lib): run rustfmt and enforce in CI

.github/workflows/CI.yml

@@ -9,9 +9,31 @@ env:
   RUST_BACKTRACE: 1
 
 jobs:
+  style:
+    name: Check Style
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v1
+
+      - name: Install Rust
+        uses: actions-rs/toolchain@v1
+        with:
+          profile: minimal
+          toolchain: stable
+          override: true
+          components: rustfmt
+
+      - name: cargo fmt --check
+        uses: actions-rs/cargo@v1
+        with:
+          command: fmt
+          args: --all -- --check
+
+
   test:
     name: Test ${{ matrix.rust }} on ${{ matrix.os }}
-
+    needs: [style]
     strategy:
       matrix:
         rust: