Updated contribution docs (#187)

Author: GrahamCampbell

.github/CONTRIBUTING.md

@@ -2,16 +2,16 @@
 
 Contributions are **welcome** and will be fully **credited**.
 
-We accept contributions via pull requests on Github. Please review these guidelines before continuing.
+We accept contributions via pull requests on GitHub. Please review these guidelines before continuing.
 
 ## Guidelines
 
 * Please follow the [PSR-12 Coding Style Guide](https://www.php-fig.org/psr/psr-12/), enforced by [StyleCI](https://styleci.io/).
 * Ensure that the current tests pass, and if you've added something new, add the tests where relevant.
-* Send a coherent commit history, making sure each individual commit in your pull request is meaningful.
+* Send a coherent commit history, making sure each commit in your pull request is meaningful.
 * You may need to [rebase](https://git-scm.com/book/en/v2/Git-Branching-Rebasing) to avoid merge conflicts.
-* If you are changing or adding to the behaviour or public api, you may need to update the docs.
-* Please remember that we follow [SemVer](https://semver.org/).
+* If you are changing or adding to the behaviour or public API, you may need to update the docs.
+* Please remember that we follow [Semantic Versioning](https://semver.org/).
 
 ## Running Tests
 
@@ -29,4 +29,4 @@ $ vendor/bin/phpunit
 
 * A script `test-git-version.sh` is available in repository to test gitlib against many git versions.
 * The tests will be automatically run by [GitHub Actions](https://github.com/features/actions) against pull requests.
-* We also have [StyleCI](https://styleci.io/) setup to automatically fix any code style issues.
+* We also have [StyleCI](https://styleci.io/) set up to automatically fix any code style issues.

.github/SECURITY.md

@@ -3,8 +3,8 @@
 ## Supported Versions
 
 After each new major release, the previous release will be supported for no
-less than 1 year, unless explictly stated otherwise. This may mean that there
-are multiple supported versions at any given time.
+less than 12 months, unless explictly stated otherwise. This may mean that
+there are multiple supported versions at any given time.
 
 ## Reporting a Vulnerability