Refactored common hook code into new NickelHook library (#64)

.github/workflows/release.yaml

@@ -9,6 +9,8 @@ jobs:
     steps:
     - name: Checkout
       uses: actions/checkout@v1
+      with:
+        submodules: true
     - name: Build
       run: make all koboroot
     - name: Release