rm python 3.6 builds, add 3.8

Author: donovanr

.github/workflows/build-master.yml

@@ -16,7 +16,7 @@ jobs:
     strategy:
       max-parallel: 6
       matrix:
-        python-version: [3.6, 3.7]
+        python-version: [3.7, 3.8]
         os: [ubuntu-latest, windows-latest, macOS-latest]
 
     steps:

.github/workflows/test-and-lint.yml

@@ -8,8 +8,8 @@ jobs:
     strategy:
       max-parallel: 6
       matrix:
-        python-version: [3.6, 3.7]
-        os: [ubuntu-latest, windows-latest, macOS-latest]
+        python-version: [3.7, 3.8]
+        os: [ubuntu-latest]
 
     steps:
     - uses: actions/checkout@v2