Don't run integration specs in lefthook
What does this MR do and why?
Running integration specs like yml_spec.rb takes 15s of total 17s.
This is slow when run in lefthook before each push and might annoy developers.
For this reason, we exclude these specs. They are still run in CI.
Because we filter spec/ now the coverage decreased to 98.73.
Edited by Peter Leitzen