chore: update PR template (#1508)

Updated this PR template to include a section to describe how the changes will be validated, with the goal to add the validation criteria to the report as we are developing, which can speed up the validation process and force us to think of how the validation will be done while we are developing instead of ending up adding stuff last minute.

#### Changed

- Changed PR template to include a validation section

.github/PULL_REQUEST_TEMPLATE.md

@@ -75,9 +75,6 @@
 
 ## Clinical Genomics Stockholm
 
-<details>
-<summary></summary>
-
 <!-- Do not reveal clinical data, and if applicable, place it within the internal Google Drive directory. -->
 
 ### Documentation
@@ -125,7 +122,24 @@
     - [x] N/A
     - [ ] Updated: [Link]
 
-</details>
+### Validation criteria
+
+<!-- Create validation criteria for this PR or mark as unnecessary. -->
+
+Validation criteria to be added to validation report PR: [LINK-TO-VALIDATION-REPORT-PR from the [validations repository](https://github.com/Clinical-Genomics/validations/)]
+
+**Version specific criteria**
+
+- Text here or N/A
+
+
+
+> [!IMPORTANT]
+> One of the below checkboxes for validation need to be checked 
+
+- [ ] Added version specific validation criteria to validation report
+- [ ] Changes validated in standard sections: [validation-section]
+- [ ] Validation criteria not necessary
 
 ## Checklist
 
@@ -139,6 +153,8 @@
     - [ ] Linked relevant user stories or issues to the PR.
 - **Documentation**
     - [ ] Verified and updated documentation if necessary.
+- **Validation criteria**
+    - [ ] Completed the validation criteria section of the template.
 - **Tests**
     - [ ] Described and tested the functionality addressed in the PR.
     - [ ] Ensured integration of the new code with existing workflows.
@@ -155,6 +171,8 @@
     - [ ] Code follows the project's coding standards and style guide.
 - **Documentation**
     - [ ] Pipeline changes are well-documented in the CHANGELOG and relevant documentation.
+- **Validation criteria**
+    - [ ] The author has completed the validation criteria section of the template
 - **Tests**
     - [ ] The author provided a description of their manual testing, including consideration of edge cases and boundary
       conditions where applicable, with satisfactory results.