net/bwping: Update to 2.2

• Usage info now includes the package version
• Manual definition of feature test macros has been replaced with Autoconf's AC_USE_SYSTEM_EXTENSIONS
• Dropped support for gettimeofday() in favor of clock_gettime()
• Various minor fixes and improvements

Changelog: https://github.com/oleg-derevenetz/bwping/releases/tag/RELEASE_2.2

PR: 251429
Submitted by: Oleg Derevenetz <oleg.derevenetz@gmail.com> (maintainer)
Approved by: arrowd, tcberner (mentors, implicit)