Rename workflow file

Author: randoum

.github/workflows/main.yml .github/workflows/unittest.yml.github/workflows/main.yml renamed to .github/workflows/unittest.yml

@@ -3,7 +3,7 @@ name: Unit test
 on: [push, pull_request]
 
 jobs:
-  build:
+  unit_test:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix: