docs: fix missing closing </details> tag in PR template

Signed-off-by: Harsh Sachdeva <sachdevaharsh2003@gmail.com>

Author: HarshSachdeva01

.github/pull_request_template.md

@@ -64,4 +64,4 @@ Please check the type of change your pull request introduces. Remove all that is
 
 Done! 🎉
 You're now ready to test this.
-<details>
+</details>