Use pylint-learn as the pylint version, if installed

.. this allows a user to install the specific version of pylint
required, under the specific name:
```
pipx install --suffix -learn pylint==2.7.1
```
and run pylint_check more easily locally.

README.md

@@ -20,3 +20,14 @@ This is a work in progress.
 
 [learn]: https://learn.adafruit.com/
 
+## Running pylint locally
+Install a specific version of pylint under the name "pylint-learn":
+```
+pip instal pipx
+pipx install --suffix -learn pylint==2.7.1
+```
+Then use the `pylint_check` script to run pylint on the files or directories
+of your choice:
+```
+./pylint_check CircuitPython_Cool_Project
+```

pylint_check.sh

@@ -1,6 +1,6 @@
 #!/bin/bash
 
-PYLINT="`type -p pylint3 2>/dev/null || type -p pylint`"
+PYLINT="`type -p pylint-learn 2>/dev/null || type -p pylint3 2>/dev/null || type -p pylint`"
 echo "Using pylint bin at $PYLINT"
 
 # Use * as the default argument to avoid descending into hidden directories like .git