Prepare 0.39.0 release

[Jim Garrison (garrison)]

• Merge issues on the milestone
• Merge this PR
• Push a tag

Some notes:

• At some point, we'll likely want to configure GitHub Actions to make a release from the tag on GitHub. This is simple enough that we might as well do it for this release, even though I don't feel it is strictly necessary to make the release
• This bumps the version even though there has not yet been a tagged 0.38.0 release. I chose to do this because the version number 0.38.0 has been used to distribute an initial version of this package in JuliaPackaging/Yggdrasil, and there has been an API change since then, in Add estimator job support #11. Bumping the version is thus best from the perspective of QiskitIBMRuntimeC.jl.

[Matthew Treinish (mtreinish)]

I agree it's time to tag the next/first release. But the last PR I'd like to make sure we include for the 0.39 tag is: #14