Merge pull request #3884 from TomJGooding/docs-readme-update-python-version

docs(readme): update python version

Author: davep

README.md

@@ -36,7 +36,7 @@ On modern terminal software (installed by default on most systems), Textual apps
 
 ## Compatibility
 
-Textual runs on Linux, macOS, and Windows. Textual requires Python 3.7 or above.
+Textual runs on Linux, macOS, and Windows. Textual requires Python 3.8 or above.
 
 ## Installing