build: remove pypy

Author: lucagiove

.github/workflows/pythonapp.yml

@@ -11,12 +11,7 @@ jobs:
     strategy:
       matrix:
         os: [ ubuntu-latest, macos-latest, windows-latest ]
-        python-version: [ 2.7, 3.7, 3.8, 3.x, pypy3.x ]
-        exclude:
-          - os: macos-latest
-            python-version: pypy3
-          - os: windows-latest
-            python-version: pypy3
+        python-version: [ 2.7, 3.7, 3.8, 3.x ]
     steps:
       - uses: actions/checkout@v2
       - name: Set up Python