Name should not be required when updating job group

[kalikiana]

None of the other properties are required and the group is identified by its ID when updating an existing job group.

[Martchus]

Looks generally good. Can you start the commit message with a verb in imperative following our usual style?

[kalikiana]

Note I need to investigate the unit tests, but since this is ad-hoc work I am not prioritizing it right now:

    #   Failed test '400 Bad Request'                                                               
    #   at t/api/10-jobgroups.t line 450.                                                           
    #          got: '200'                                                                           
    #     expected: '400'                                                                           
                                                                                                    
    #   Failed test 'Unable to update parent group with empty or blank name'                        
    #   at t/api/10-jobgroups.t line 450.                                                           
    #          got: undef                                                                           
    #     expected: 'Erroneous parameters (name missing)'                                           
                                                                                                    
    #   Failed test '400 Bad Request'                                                               
    #   at t/api/10-jobgroups.t line 454.                                                           
    #          got: '200'                                                                           
    #     expected: '400'                                                                           
                                                                                                    
    #   Failed test 'Unable to update job group with empty or blank name'                           
    #   at t/api/10-jobgroups.t line 454.                                                           
    #          got: undef                                                                           
    #     expected: 'Erroneous parameters (name missing)'                                           
    # Looks like you failed 4 tests of 12.                                                          
                                                                                                    
#   Failed test 'prevent update parent/job group with empty or blank name'                          
#   at t/api/10-jobgroups.t line 459.                                                               
# Looks like you failed 1 test of 13