chore: update pull request template according to commitlint

Updates pull request template to avoid inconsistencies.

Signed-off-by: Taimoor Zaeem <taimoorzaeem@gmail.com>

.github/PULL_REQUEST_TEMPLATE.md

@@ -4,17 +4,18 @@ When submitting a new feature or fix:
 - Add a new entry to the CHANGELOG - https://github.com/PostgREST/postgrest/blob/main/CHANGELOG.md#unreleased
 - If relevant, update the docs
 - Use a prefix for the PR title or commits, e.g. "fix: description of the fix".
-  + `fix`, bug fixes
-  + `feat`, new features added
-  + `perf`, performance improvements
-  + `docs`, updating the documentation
-  + `nix`, related to the Nix development environment
-  + `ci`, related to the Continuous Integration modules
-  + `test`, related to the testing modules
-  + `refactor`, refactoring code
-  + `deprecate`, deprecating a feature
-  + `changelog`, updating the CHANGELOG
-  + `chore`, maintenance (build process, updating sponsors, etc.)
+  + `add`, Add a new feature
+  + `amend`, To amend an unrealease commit
+  + `change`, Breaking changes
+  + `chore`, Maintenance, update sponsors, changelog, readme etc
+  + `ci`, CI configuration files and scripts
+  + `docs`, Documentation
+  + `fix`, Bug fix
+  + `nix`, Related to Nix
+  + `perf`, Performance improvements
+  + `refactor`, Refactoring code
+  + `remove`, Remove a feature or fix
+  + `test`, Adding tests
   + Other prefixes may be used if necessary
 - If there's a breaking change, add `BREAKING CHANGE` and an explanation to your commit message
 -->