Remove pydata-sphinx-theme fix

Needs 2i2c-org/sphinx-2i2c-theme#17 for sphinx-book-theme fix

Author: pnasrat

docs/requirements.txt

@@ -6,6 +6,4 @@ sphinx-autobuild
 sphinx-copybutton
 sphinx-design
 # Pin pydate-sphinx-theme
-# Remove after https://github.com/pydata/pydata-sphinx-theme/issues/1274 has been fixed
-pydata-sphinx-theme==0.13.1 
 git+https://github.com/2i2c-org/sphinx-2i2c-theme