security/bsmtrace: switch MAINTAINER over to csjp@

alm@ and csjp@ are both upstream maintainers of bsmtrace; they've decided to
transfer maintainership of bsmtrace over to csjp@. PORTREVISION bump to
reflect the new maintainer in the package.

Approved by: alm (maintainer, via e-mail)
Approved by: koobs (mentor, ports)
MFH: 2020Q2 (blanket: metadata update, MAINTAINER consistency)