Delete my pull request template (#23303)

The PR template that I added a few months ago
doesn't seem to be adding any value to platform PRs.

.github/PULL_REQUEST_TEMPLATE.md

@@ -1,18 +0,0 @@
-### Please consider the following when opening a pull request:
-
-- Link to the relevant JIRA ticket(s) and tag any relevant team(s).
-- Squash your changes down into one or more discrete commits.
-  In each commit, include description that could help a developer
-  several months from now.
-- If running `make upgrade`, run _as close to the time of merging as possible_
-  to avoid accidentally downgrading someone else's package.
-  Put the output of `make upgrade` in its own separate commit,
-  decoupled from other code changes.
-- Aim for comprehensive test coverage, but remember that
-  automated testing isn't a substitute for manual verification.
-- Carefully consider naming, code organization, dependencies when adding new code.
-  Code that is amenable to refactoring and improvement benefits all platform developers,
-  especially given the size and scope of edx-platform.
-  Consult existing Architectural Decision Records (ADRs),
-  including those concerning the app(s) you are changing and
-  [those concerning edx-platform as a whole](https://github.com/edx/edx-platform/tree/master/docs/decisions).