gitlint: adapt configuration to deal with migration warnings

Get rid of this warning:

WARNING: I4 - ignore-by-author-name: gitlint will be switching from
using Python regex 'match' (match beginning) to 'search' (match
anywhere) semantics.  Please review your ignore-by-author-name.regex
option accordingly. To remove this warning, set
general.regex-style-search=True. More details:
https://jorisroovers.github.io/gitlint/configuration/#regex-style-search



Signed-off-by: Anas Nashif <anas.nashif@intel.com>