Fix ghpages python version string (#1286)

Similar issue as this:
actions/setup-python#401 (comment)

`3.10` gets interpreted as `3.1` when I want it to be `"3.10"`.

.github/workflows/sphinx.yml

@@ -24,7 +24,7 @@ jobs:
       - name: Install Python
         uses: actions/setup-python@v2
         with:
-          python-version: 3.10
+          python-version: "3.10"
       # https://docs.github.com/en/actions/guides/building-and-testing-python#caching-dependencies
       # ^-- How to set up caching for pip on Ubuntu
       - name: Cache pip

setup.py

@@ -1,7 +1,7 @@
 from setuptools import find_packages
 from setuptools import setup
 
-__version__ = '0.90.0rc1'
+__version__ = '0.90.0rc2'
 
 
 setup(