change runs-on to make github actions work

Author: jxmorris12

.github/workflows/test.yml

@@ -12,10 +12,10 @@ on:
 jobs:
   build:
 
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     strategy:
       matrix:
-        python-version: [3.6.15, 3.7.15, 3.8.16]
+        python-version: [3.6, 3.7, 3.8]
 
     steps:
     - uses: actions/checkout@v2