Ultra minor spelling fix (#5029)

.github/PULL_REQUEST_TEMPLATE.md

@@ -1,6 +1,6 @@
 ### PR checklist
 
-- [ ] Read the [contribution guildelines](https://github.com/swagger-api/swagger-codegen/blob/master/CONTRIBUTING.md).
+- [ ] Read the [contribution guidelines](https://github.com/swagger-api/swagger-codegen/blob/master/CONTRIBUTING.md).
 - [ ] Ran the shell/batch script under `./bin/` to update Petstore sample so that CIs can verify the change. (For instance, only need to run `./bin/{LANG}-petstore.sh` and `./bin/security/{LANG}-petstore.sh` if updating the {LANG} (e.g. php, ruby, python, etc) code generator or {LANG} client's mustache templates)
 - [ ] Filed the PR against the correct branch: master for non-breaking changes and `2.3.0` branch for breaking (non-backward compatible) changes.