Add Eric Windisch to MAINTAINER for tarsum

This code is vital to the security of the project and it is important
we assure it is well-maintained and guarded.

I am vested in assuring this code maintains security and
provides as much compatibility as possible between releases.

Signed-off-by: Eric Windisch <eric@windisch.us>
Merge pull request #7647 from ewindisch/erw-tarsum-maintainer

Add Eric Windisch to MAINTAINER for tarsum