docs: improve setup instructions for pre-commit

Author: slhck

docs/README.md

@@ -101,6 +101,7 @@ cz commit -s
 ```
 
 ### Integrating with Pre-commit
+
 Commitizen can lint your commit message for you with `cz check`.
 You can integrate this in your [pre-commit](https://pre-commit.com/) config with:
 
@@ -119,6 +120,12 @@ After the configuration is added, you'll need to run
 pre-commit install --hook-type commit-msg
 ```
 
+Note that pre-commit discourages using `master` as a revision, and the above command will print a warning. You should replace the `master` revision with the [latest tag](https://github.com/commitizen-tools/commitizen/tags). This can be done automatically with:
+
+```sh
+pre-commit autoupdate
+```
+
 Read more about the `check` command [here](check.md).
 
 ### Help