chore(ci) fix ubuntu 22.04 release docker image

[casimiro]

In the commit 1a0759b, the Dockerfile used to build the ubuntu 22.04 release image was changed to install clang-15 instead of clang -- applying the intended bump.

It lacked, however, an update-alternative call making clang available as a link to clang-15.

[codecov]

Codecov Report

Merging #416 (73dc902) into main (1c1588a) will increase coverage by 0.00494%.
Report is 1 commits behind head on main.
The diff coverage is n/a.

Additional details and impacted files

@@                 Coverage Diff                 @@
##                main        #416         +/-   ##
===================================================
+ Coverage   90.25116%   90.25610%   +0.00494%     
===================================================
  Files             46          46                 
  Lines           8401        8395          -6     
===================================================
- Hits            7582        7577          -5     
+ Misses           819         818          -1     

see 3 files with indirect coverage changes