Add Bella to git-crypt keyring

New collaborators:

	DB1D650A Amrou Bellalouna <[email protected]>

The key has been verified and signed by both Joe and me. Chris was MIA
but approved it ahead of time.

Approved-by: Joe Banks <[email protected]>
Approved-by: Chris Lovering <[email protected]>

Author: jchristgit