MSRV policy feedback

[jhpratt]

time has officially adopted an N-2 MSRV policy. Full details can be found in the README.

In terms of immediate effects, there are none. Of all library and language features that I am tracking, only one has been stabilized and is awaiting the date to bump MSRV. As a strictly internal change, it's subject to the N-4 policy. This is nearly the same as the six months I had previously guaranteed.

Please use this discussion to provide feedback on situations where the MSRV policy of time has caused you issues. One point that has been raised is large (presumably corporate) repositories that need to update a dependency, and this cascades into requiring an MSRV bump and updating various nightly features. If this is you, speak up!

What this discussion is not is a place to rehash the discussion about the policy in general. I am seeking feedback on where the policy has caused demonstrably extraneous effort or a concrete inability to do something desired (other than maintaining your own, lower MSRV).