Add a CONTRIBUTING.md doc

Author: borntyping

README.md

@@ -20,7 +20,7 @@ support Python 2.6 and above.
 [colorama] is included as a required dependency and initialised when using 
 colorlog on Windows.
 
-This library is almost a decade old and supported a wide set of Python versions
+This library is over a decade old and supported a wide set of Python versions
 for most of its life, which has made it a difficult library to add new features
 to. colorlog 6 may break backwards compatibility so that newer features
 can be added more easily, but may still not accept all changes or feature

docs/CONTRIBUTING.md

@@ -0,0 +1,19 @@
+# Contributing to colorlog
+
+## New features
+
+Open a thread in the "[Discussions]" section of the GitHub repository before doing any significant work on a new feature. This library is over a decade old, and my priority in maintaining it is stability rather than features. See the [Status](../README.md#Status]) section of the README file for more information.
+
+## Bugfixes
+
+_Please_ provide a simple way to reproduce any bug you encounter when opening an issue. It's very common for bugs to be reported for this library that are actually caused by the calling code or another library being used alongside it.
+
+## Pull requests
+
+Open pull requests against the `main` branch.
+
+Make sure your changes pass the test suite, which runs tests against most recent versions of Python 3 and checks the `black` formatter makes no changes.
+   * You can run tests locally with `tox` if you have suitable versions of Python 3 installed...
+   * ...or use the GitHub Actions pipeline which will run automatically once you open a pull request. 
+
+[Discussions]: https://github.com/borntyping/python-colorlog/discussions