`v1.16.2` release preparation

[alejandro-vaz]

this release addresses

• the correct drop behavior with the may_dangle feature in Fix element ownership tracking with may_dangle #594
• the new retain implementation backported from v2 in Backport v2’s retain implementation to v1 #596

both from @charliermarsh

checklist

• figure out if any other changes are needed or desired
• verify documentation builds
• version bump
• create tag and release with changelog
• publish

this release is scheduled for the 27th this month

[alejandro-vaz]

note: I'll look at this tomorrow, but it may be that the new implementation of retain could not be backwards compatible because of its panic behavior

I doubt anything downstream relies on the old behavior, but to keep us safe this may be v1.17.0

will look at it tomorrow morning.

[alejandro-vaz]

I've taken a look at it. since it's only panic behavior and the algorithm, and it does not change observable behavior except in case of panic, it is sensible to keep it as v1.16.2