[CI] Add fourmolu #10

Author: 4TT1L4

.github/workflows/haskell.yml

@@ -93,11 +93,10 @@ jobs:
         sudo ldconfig
     - name: Update dependencies (cabal)
       run: cabal update
-    # TODO: [CI] Add fourmolu #10
     - name: Install fourmolu
       run: cabal install fourmolu
-    #- name: Run checks (fourmolu)
-    #  run: fourmolu --mode check src
+    - name: Run checks (fourmolu)
+      run: fourmolu --mode check src
     - name: Build dependencies (cabal)
       run: cabal build --only-dependencies --enable-tests --enable-benchmarks
     - name: Build all targets (cabal)