Use nix-build in github-actions

.github/workflows/haskell.yml

@@ -4,16 +4,12 @@ on: [push]
 
 jobs:
   build:
-   
+
     runs-on: ubuntu-latest
 
     steps:
     - uses: actions/checkout@v1
-    - name: Install dependencies
-      run: cabal install --only-dependencies --enable-tests
-    - name: Build
-      run: |
-        cabal configure --enable-tests
-        cabal build
-    - name: Run tests
-      run: cabal test
+    - name: Nix Build
+      with:
+        args: default.nix
+      uses: ./.github/actions/nix-build