NEWS.md: add release notes for v0.38.0

[jameshcorbett]

Problem: there are no release notes for v0.38.0.

Add them.

[grondo]

@trws , anything pending that should make it into this release?

[grondo]

LGTM if @trws agrees. Thanks!

[trws]

This is a decent place to break IMO, I'd recommend explicitly noting the new compiler requirements and the fact that we dropped support for the default focal compiler in this release in the notes though.

[jameshcorbett]

Done for the compiler versions. I think the focal drop was from last release? In 0.37.0 we have

### Build/Testsuite
 * actions/docker: add ~el9~,f40,noble drop focal (#1257)

Setting MWP.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 75.3%. Comparing base (758258e) to head (3276957).
Report is 2 commits behind head on master.

Additional details and impacted files

@@          Coverage Diff           @@
##           master   #1288   +/-   ##
======================================
  Coverage    75.3%   75.3%           
======================================
  Files         110     110           
  Lines       15236   15236           
======================================
  Hits        11482   11482           
  Misses       3754    3754           

[trws]

I think that's right, thanks!