[README] docs, changelog, flake, cabal improvements

2 jobs for master in 1 minute and 54 seconds (queued for 5 seconds)
Status Job ID Name Coverage
  Build
failed #18444
build

00:01:54

 
  Integration Tests
skipped #18445
integration-tests
 
Name Stage Failure
failed
build Build
$ cabal update
Config file path source is default config file.
Config file not found: /root/.cabal/config
Writing default configuration to /root/.cabal/config
Error: cabal: Cannot find the program 'ghc'. User-specified path 'ghc-9.6.6'
does not refer to an executable and the program is not on the system path.

Cleaning up project directory and file based variables
ERROR: Job failed: exit code 1