Adding missing documentation parameters

[joabda]

Issue Description:
In the pubhub documentation for create_dhcp_pool the lease parameters are missing.

Changes:
I proposed to replace the current function's documentation with the following:

def create_dhcp_pool(
    device, pool_name, network, mask, router_id,lease_days,lease_hrs,lease_mins
):
    """ Create DHCP pool
        Args:
            device ('obj'): device to use
            pool_name ('str'): name of the pool to be created
            network ('str'): IP of the network pool
            mask ('str'): Subnet mask of the network pool
            router_id ('str'): Default router ID
            lease_days ('str'): Number of days for the lease
            lease_hrs ('str'): Number of hours for the lease
            lease_mins ('str'): Number of minutes for the lease
        Returns:
            None
        Raises:
            SubCommandFailure: Failed creating dhcp pool
    """

Unit Testing:
None required, changes only affect comment part.

[joabda]

@GerriorL what about this failing run?

[GerriorL]

@GerriorL what about this failing run?

We don't support 3.7 anymore

[joabda]

@GerriorL Anything required on my side to merge this?

[omehrabi]

could you merge master and push again

[joabda]

@omehrabi Done

[joabda]

@GerriorL @omehrabi Anything required on my side to merge this?