CONTRIBUTING.md in zip_tricks-5.5.0 vs CONTRIBUTING.md in zip_tricks-5.6.0

@@ -25,11 +25,11 @@
 
 The issue tracker is the preferred channel for [bug reports](#bug-reports),
 [feature requests](#feature-requests) and [submitting pull
 requests](#pull-requests), but please respect the following restrictions:
 
-* Please **do not** derail or troll issues. Keep the discussion on topic and respect the opinions of others. Adhere to the principles set out in the [Code of Conduct](https://github.com/WeTransfer/zip_tricks/blob/master/CODE_OF_CONDUCT.md).
+* Please **do not** derail or troll issues. Keep the discussion on topic and respect the opinions of others. Adhere to the principles set out in the [Code of Conduct](https://github.com/WeTransfer/zip_tricks/blob/main/CODE_OF_CONDUCT.md).
 
 ## Bug reports
 
 A bug is a _demonstrable problem_ that is caused by code in the repository.
 
@@ -39,11 +39,11 @@
 
 1. **Use the GitHub issue search** — check if the issue has already been
    reported.
 
 2. **Check if the issue has been fixed** — try to reproduce it using the
-   latest `master` branch in the repository.
+   latest `main` branch in the repository.
 
 3. **Isolate the problem** — create a [reduced test
    case](http://css-tricks.com/reduced-test-cases/) and a live example.
 
 A good bug report shouldn't leave others needing to chase you up for more
@@ -94,11 +94,11 @@
 accurate comments, etc.) and any other requirements (such as test coverage).
 
 The project uses Rubocop which can be run using `bundle exec rubocop`. The test
 suite can be run with `bundle exec rspec`. You are also encouraged to use the
 script in the `testing` directory to create test files that you can then verify
-with various zip/unzip utilities. Further instructions are [here](https://github.com/WeTransfer/zip_tricks/blob/master/testing/README_TESTING.md).  
+with various zip/unzip utilities. Further instructions are [here](https://github.com/WeTransfer/zip_tricks/blob/main/testing/README_TESTING.md).  
 
 Follow this process if you'd like your work considered for inclusion in the
 project:
 
 1. [Fork](http://help.github.com/fork-a-repo/) the project, clone your fork,
@@ -146,6 +146,6 @@
 7. [Open a Pull Request](https://help.github.com/articles/using-pull-requests/)
     with a clear title and description.
 
 **IMPORTANT**: By submitting a patch, you agree to allow the project owner to
 license your work under the same license as that used by the project, which you
-can see by clicking [here](https://github.com/WeTransfer/zip_tricks/blob/master/LICENSE.txt). 
+can see by clicking [here](https://github.com/WeTransfer/zip_tricks/blob/main/LICENSE.txt).