Update Sourceview to 4.2.

Closes: #256
3 jobs for master in 25 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Build
failed #729
build

00:00:25

 
  Test
skipped #731
allowed to fail
code_quality
skipped #730
test
 
Name Stage Failure
failed
build Build
Checking out 86086570 as master...
Skipping Git submodules setup
$ # Auto DevOps variables and functions # collapsed multi-line command
$ setup_docker
$ build
Logging to GitLab Container Registry with CI credentials...
WARNING! Using --password via the CLI is insecure. Use --password-stdin.
Error response from daemon: Get https://registry-1.docker.io/v2/: unauthorized: incorrect username or password
ERROR: Job failed: exit code 1