using python 3.10

in the github action for building documentation, i got this:

```
Configuration error:
There is a programmable error in your configuration file:
Traceback (most recent call last):
  File "/usr/local/lib/python3.8/site-packages/sphinx/config.py", line 348, in eval_config_file
    execfile_(filename, namespace)
  File "/usr/local/lib/python3.8/site-packages/sphinx/util/pycompat.py", line 81, in execfile_
    exec(code, _globals)
  File "/github/workspace/docs/conf.py", line 42, in <module>
    import markdown2canvas
  File "/github/workspace/markdown2canvas/__init__.py", line 10, in <module>
    logging.basicConfig(encoding='utf-8')
  File "/usr/local/lib/python3.8/logging/__init__.py", line 1997, in basicConfig
    raise ValueError('Unrecognised argument(s): %s' % keys)
ValueError: Unrecognised argument(s): encoding
make: *** [Makefile:20: html] Error 2
```

.github/workflows/documentation.yml

@@ -5,12 +5,19 @@ on: push
 permissions:
   contents: write
 
+
+
 jobs:
   build:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@master
 
+    - name: Set up Python 3.10
+      uses: actions/setup-python@v2
+      with:
+        python-version: '3.10'
+
     - name: Build HTML
       uses: ammaraskar/sphinx-action@master
       with: