Drop WioTerminal support, update dependencies.

Author: mrstegeman

.github/workflows/build.yml

@@ -19,10 +19,10 @@ jobs:
         source: '.'
         extensions: 'h,cpp,ino'
         clangFormatVersion: 9
-    - name: Set up Python 3.7
-      uses: actions/setup-python@v1
+    - name: Set up Python 3.9
+      uses: actions/setup-python@v2
       with:
-        python-version: 3.7
+        python-version: 3.9
     - name: Install dependencies
       run: |
         python -m pip install --upgrade pip