bugs: combine dependent partially stabilized version with newly requested version

[mgorny]

$ git rev-parse HEAD
187bd7adbec88b8f6f75607bca811c645b20618d
$ pkgdev bugs pyarrow pandas
Checking =dev-python/pyarrow-17.0.0 on 'amd64'
Checking =dev-python/pandas-2.2.2-r1 on 'amd64 arm64 x86'
Checking =dev-libs/apache-arrow-17.0.0 on 'amd64' [added for =dev-python/pyarrow-17.0.0]
Checking =dev-libs/apache-arrow-16.1.0 on 'arm64 x86' [added for =dev-python/pandas-2.2.2-r1]
Checking =dev-libs/thrift-0.16.0-r2 on 'arm64 x86' [added for =dev-libs/apache-arrow-16.1.0]
Merging =dev-libs/thrift-0.16.0-r2 into =dev-libs/apache-arrow-16.1.0
Merging =dev-libs/apache-arrow-16.1.0, =dev-libs/thrift-0.16.0-r2 into =dev-python/pandas-2.2.2-r1

What I'd really love to see happen here is pkgdev figure out that =dev-libs/apache-arrow-16.1.0 was partially stabilized and we should take 17.0.0 for all arches.

[mgorny]

Or to put it more algorithmically, once =dev-libs/apache-arrow-16.1.0 is stabilized, these keywords would naturally become targets for the 17.0.0 stablereq.