docs: add a checklist item to PR template && fix broken link

[jordaniza]

Description

On the fly task to add a QA checklist item to the list below

Type of change

• [x] New feature (non-breaking change which adds functionality)

Checklist:

• [x] I have selected the correct base branch.
• [ ] I have performed a self-review of my own code.
• [ ] I have commented my code, particularly in hard-to-understand areas.
• [ ] My changes generate no new warnings.
• [ ] Any dependent changes have been merged and published in downstream modules.
• [ ] I ran all tests with success and extended them if necessary.
• [ ] I have updated the CHANGELOG.md file in the root folder.
• [ ] I have updated the DEPLOYMENT_CHECKLIST file in the root folder.
• [ ] I have updated the UPDATE_CHECKLIST file in the root folder.
• [ ] I have updated the Subgraph and added a QA URL to the description of this PR.