Release notes generator fails to pick up BGPCEP Jiras correctly

In Release Notes: PCEP-X -> BGPCEP-X
https://docs.opendaylight.org/en/stable-neon/release-notes/release-notes-neon-sr3.html

It seems like BGPCEP is being picked up as PCEP. Might be related to the support for Bugzilla considering Bugzilla IDs are in the form BUG-# perhaps the regex is incorrectly picking up the BG part as a Bugzilla.

On the otherhand I do not expect any projects to still be using Bugzilla IDs so might be a good time to remove the code that scans for bugzilla IDs from the generator script.