chore: add lint to CI

.github/workflows/ci.yml

@@ -21,22 +21,41 @@ jobs:
         working-directory: "halo2-base"
         run: |
           cargo test
-      - name: Run halo2-ecc tests MockProver
+      - name: Run halo2-ecc tests (mock prover)
         working-directory: "halo2-ecc"
         run: |
-          cargo test -- --skip bench
+          cargo test --jobs=1 -- --skip bench
       - name: Run halo2-ecc tests (real prover)
         working-directory: "halo2-ecc"
         run: |
-          cargo test --release -- bench_secp256k1_ecdsa
-          cargo test --release -- bench_ec_add
           mv configs/bn254/bench_fixed_msm.t.config configs/bn254/bench_fixed_msm.config
-          cargo test --release -- bench_fixed_base_msm
           mv configs/bn254/bench_msm.t.config configs/bn254/bench_msm.config
-          cargo test --release -- bench_msm
           mv configs/bn254/bench_pairing.t.config configs/bn254/bench_pairing.config
-          cargo test --release -- bench_pairing
+          cargo test --release --jobs=1 -- bench
       - name: Run zkevm-keccak tests
         working-directory: "hashes/zkevm-keccak"
         run: |
-          cargo test
+          cargo test --jobs=1
+
+  lint:
+    name: Lint
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: Install toolchain
+        uses: actions-rs/toolchain@v1
+        with:
+          profile: minimal
+          override: false
+          components: rustfmt, clippy
+
+      - uses: Swatinem/rust-cache@v1
+        with:
+          cache-on-failure: true
+
+      - name: Run fmt
+        run: cargo fmt --all -- --check
+
+      - name: Run clippy
+        run: cargo clippy --all -- -D warnings