Fix links in pull request template (#7371)

.github/pull_request_template.md

@@ -6,8 +6,8 @@
 
 # Contributor Checklist
 
-- [ ] Format the title [according the contribution guidelines](/CONTRIBUTING.md#title-format)
-- [ ] Assign the `type:` and (`comp:` or `inst:`) labels in addition to [any usefull labels](/CONTRIBUTING.md#labels)
+- [ ] Format the title [according the contribution guidelines](https://github.com/DataDog/dd-trace-java/blob/master/CONTRIBUTING.md#title-format)
+- [ ] Assign the `type:` and (`comp:` or `inst:`) labels in addition to [any usefull labels](https://github.com/DataDog/dd-trace-java/blob/master/CONTRIBUTING.md#labels)
 - [ ] Squash your commits prior merging or merge using GitHub's [Squash and merge](https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/incorporating-changes-from-a-pull-request/about-pull-request-merges#squash-and-merge-your-commits)
 - [ ] Don't use `close`, `fix` or any [linking keywords](https://docs.github.com/en/issues/tracking-your-work-with-issues/linking-a-pull-request-to-an-issue#linking-a-pull-request-to-an-issue-using-a-keyword) when referencing an issue.  
   Use `solves` instead, and assign the PR [milestone](https://github.com/DataDog/dd-trace-java/milestones) to the issue