Fix changing solver to sequential

Merged Hamza Oukili requested to merge fix/changesolver-to-sequential into master

What this MR does / why does DuMux need it:

Changing solver to sequential otherwise the test try to use parallel and fails.

Before you request a review from someone, make sure to revise the following points:

  • does the new code follow the style guide?
  • do the test pipelines pass? (see guide on how to run pipelines for a merge request)
  • is the code you changed and/or the new code you wrote covered in the test suite? (if not, extend the existing tests or write new ones)
  • does your change affect public interfaces or behavior, or, does it introduce a new feature? If so, document the change in CHANGELOG.md.
  • is the list of the header includes complete? ("include what you use")
  • all files have to end with a \n character. Make sure there is no \ No newline at end of file comment in "Changes" of this MR.
Edited by Timo Koch

Merge request reports