Upgrade devel/fstrm to version 0.6.0:

• fstrm_capture: Perform output file rotation when a SIGUSR1 signal is received. This allows fstrm_capture's output file to be rotated by logrotate or a similar external utility. (Output rotation is suppressed if fstrm_capture is writing to stdout.)

PR: 241256
Reviewed by: swills (tested build)
Approved by: freebsd@dns.company (maintainer timeout, 4 weeks)
Sponsored by: Farsight Security, Inc.