add check-bench workflow

.github/workflows/integrate.yaml

@@ -37,6 +37,28 @@ jobs:
       - run: nix build .#checks.x86_64-linux.formatCheck
         name: Run 'formatCheck' from flake.nix
 
+  check-bench:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2.4.0
+
+      - uses: cachix/install-nix-action@v16
+        name: Set up Nix and IOHK caches
+        with:
+          nix_path: nixpkgs=channel:nixos-unstable
+          extra_nix_config: |
+            trusted-public-keys = hydra.iohk.io:f/Ea+s+dFdN+3Y/G+FDgSq+a5NEWhJGzdjvKNGv0/EQ= iohk.cachix.org-1:DpRUyj7h7V830dp/i6Nti+NEO2/nhblbov/8MW7Rqoo= cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY=
+            substituters = https://hydra.iohk.io https://iohk.cachix.org https://cache.nixos.org/
+            experimental-features = nix-command flakes
+
+      - uses: cachix/cachix-action@v10
+        with:
+          name: mlabs
+          authToken: ${{ secrets.CACHIX_KEY }}
+
+      - run: nix build .#checks.x86_64-linux.benchCheck
+        name: Run 'benchCheck' from flake.nix
+
   check-build:
     runs-on: ubuntu-latest
     steps:
@@ -69,8 +91,6 @@ jobs:
       - name: Build the project
         run: nix build .#check.x86_64-linux
 
-
-
   haddock:
     runs-on: ubuntu-latest
     steps: