Updating PR Template

Highlighting that changes should be against the develop branch, and how to sign off commits.

Author: jpwsutton

.github/PULL_REQUEST_TEMPLATE.md

@@ -1,6 +1,7 @@
 Please make sure that the following boxes are checked before submitting your Pull Request, thank you!
 
+- [ ] This change is against the develop branch, **not** master.
 - [ ] You have signed the [Eclipse ECA](https://wiki.eclipse.org/ECA)
-- [ ] All of your commits have been signed-off with the correct email address (The same one that you used to sign the CLA)
+- [ ] All of your commits have been signed-off with the correct email address (The same one that you used to sign the CLA) _Hint: use the -s argument when committing_.
 - [ ] If This PR fixes an issue, that you reference the issue below. OR if this is a new issue that you are fixing straight away that you add some Description about the bug and how this will fix it.
 - [ ] If this is new functionality, You have added the appropriate Unit tests.