Install cython in github workflow

Author: bdutro-mips

.github/workflows/ubuntu-build.yml

@@ -16,7 +16,7 @@ jobs:
     - name: Install Dependencies
       run: |
         sudo apt-get update
-        sudo apt-get -y install libboost-dev
+        sudo apt-get -y install libboost-dev cython3
 
     - name: Create Build Directory
       run: cmake -E make_directory ${{runner.workspace}}/build