test only for ubuntu

Author: sumansaurabh

.github/workflows/build.yml

@@ -11,7 +11,8 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [ubuntu-20.04, macOS-10.15, windows-2019]
+        # os: [ubuntu-20.04, macOS-10.15, windows-2019]
+        os: [ubuntu-20.04]
         python-version: [3.6, 3.7, 3.8, 3.9, "3.10", 3.11, 3.12.0-rc.2]
     steps:
     - uses: actions/checkout@v2