Update action version in README

Author: MatteoH2O1999

README.md

@@ -30,15 +30,15 @@ For a more complete view on the actions see [action.yml](action.yml) or look in
 In general you could replace the original action with this one and it should already work (all its supported inputs are also supported in this one):
 
 ```yaml
-- uses: MatteoH2O1999/setup-python@v3
+- uses: MatteoH2O1999/setup-python@v4
   with:
     python-version: '3.8'
 ```
 
 But if you wish for a more optimized experience you could use inputs exclusive to this action:
 
 ```yaml
-- uses: MatteoH2O1999/setup-python@v3
+- uses: MatteoH2O1999/setup-python@v4
   with:
     python-version: '3.8'
     allow-build: info