fix: Fix changelog and broken PR template link (#675)

* Fix changelog and broken PR template link

* Use a non-relative link since our contributing guide should always be on default branch in the main repo

Author: dbudziwojskiNR

.github/PULL_REQUEST_TEMPLATE.md

@@ -12,7 +12,7 @@
 ## Checklist:
 <!-- Please check applicable options. -->
 
-- [ ] Add changelog entry following the [contributing guide](../CONTRIBUTING.md#pull-requests)
+- [ ] Add changelog entry following the [contributing guide](https://github.com/newrelic/k8s-metadata-injection/blob/main/CONTRIBUTING.md)
 - [ ] Documentation has been updated
 - [ ] This change requires changes in testing:
   - [ ] unit tests

CHANGELOG.md

@@ -7,7 +7,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## Unreleased
 
-### 🔒 Security
+### security
 - Allow pre-upgrade job pods to honor global security context settings @dpacheconr [#670](https://github.com/newrelic/k8s-metadata-injection/pull/670)
 
 ## v1.38.1 - 2025-10-20