Update CONTRIBUTING.md

Author: KarolinHem

CONTRIBUTING.md

@@ -15,7 +15,7 @@ Or you can [start a new discussion](../../discussions/new/choose) and ask your q
 
 If you find a problem with Bouncy Castle, [search if an issue already exists](../../issues).
 
-If the issue is a potential security problem, please contact us at [email protected] before posting anything public.
+If the issue is a __potential security problem__, please contact us at [email protected] before posting anything public.
 
 If a related discussion or issue doesn't exist, and the issue is not security related, you can [open a new issue](../../issues/new). An issue can be converted into a discussion if regarded as one.
 
@@ -27,6 +27,8 @@ Please note we are unable to accept contributions which cannot be released under
 
 #### Create a pull request
 
+If the issue is a __potential security problem__, please contact us at [email protected] before creating a pull request.
+
 You are welcome to send patches, under the Bouncy Castle License, as pull requests. For more information, see [Creating a pull request](https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/proposing-changes-to-your-work-with-pull-requests/creating-a-pull-request). For minor updates, you can instead choose to create an issue with short snippets of code. See above.
 
 * For contributions touching multiple files try and split up the pull request, smaller changes are easier to review and test, as well as being less likely to run into merge issues.