build: bump version to 1.5.99

This will signify that we are in the development phase. Having the 1.5.0 on
master between two major releases might be confusing.

Jira: ZEP-1100
Change-Id: Ifbea81fbb8afe544af1fb30c79cb67dadb6d731d
Signed-off-by: Anas Nashif <anas.nashif@intel.com>
1 file changed