ports-mgmt/pkg-devel: update to 1.18.99.6
Changes:
- remove backup command, do backup pkg shell .dump should be preferred as already done via periodic script
- (r)query: stricter command line validation
- (r)query: new operators: =~ ==~ and !=~
- fix merging of config files accross split upgrades
- fix a regression when executing a shell script (introduced in 1.18.99.4)