Update PR template checklist

Author: gpotter2

.github/PULL_REQUEST_TEMPLATE.md

@@ -1,11 +1,11 @@
-<!-- This is just a checklist to guide you. You can remove it safely. -->
+<!-- This is just a checklist to guide you. Please remove it if you check all items. -->
 
 **Checklist:**
 
 -   [ ] If you are new to Scapy: I have checked [CONTRIBUTING.md](https://github.com/secdev/scapy/blob/master/CONTRIBUTING.md) (esp. section submitting-pull-requests)
 -   [ ] I squashed commits belonging together
 -   [ ] I added unit tests or explained why they are not relevant
--   [ ] I executed the regression tests (using `cd test && ./run_tests` or `tox`)
+-   [ ] I executed the regression tests (using `tox`)
 -   [ ] If the PR is still not finished, please create a [Draft Pull Request](https://github.blog/2019-02-14-introducing-draft-pull-requests/)
 
 <!-- brief description what this PR will do, e.g. fixes broken dissection of XXX -->