test on Windows and macOS, too

- test 3.8 on Windows and macOS
- colorful tests
- setup.py: add long description type explicitly to make twine happy

Author: orbeckst

.github/workflows/gh-ci.yaml

@@ -26,7 +26,13 @@ jobs:
         python-version: [2.7, 3.5, 3.6, 3.7, 3.8, 3.9]
         include:
           - os: windows-latest
-            python-version: 3.7
+            python-version: 2.7	
+          - os: windows-latest
+            python-version: 3.9
+          - os: macos-latest
+            python-version: 2.7	    
+          - os: macos-latest
+            python-version: 3.9
 
     steps:
     - uses: actions/checkout@v2
@@ -58,7 +64,7 @@ jobs:
 
     - name: run unit tests
       run: |
-        pytest -v --cov=gridData --cov-report=xml ./gridData/tests
+        pytest -v --cov=gridData --cov-report=xml --color=yes ./gridData/tests
 
     - name: codecov
       uses: codecov/codecov-action@v2

setup.py

@@ -14,6 +14,7 @@
       cmdclass=versioneer.get_cmdclass(),
       description="Reading and writing of data on regular grids in Python",
       long_description=long_description,
+      long_description_content_type="text/x-rst",
       author="Oliver Beckstein",
       author_email="orbeckst@gmail.com",
       license="LGPLv3",