Click 7 support

[jayvdb]

Closes #2

[jayvdb]

ping @rbonthond , could you take a look at this

[jayvdb]

Perhaps @timofurrer, do you have the ability to help with this?

There are real users of it. c.f. github code search

I'd like to get this packaged for openSUSE, which uses Python 3.7, and I have a "large" collection of click plugins.

[timofurrer]

I've just realized, that I don't have the permissions to merge this.
@click-contrib/maintainers Can someone of you help out here? Or grant me the commit bit here?
I'm already maintaining some repos in this org ..

[untitaker]

@timofurrer not all org members have access to all repos. Please ask @rbonthond if it's ok, then I will grant you acess

[timofurrer]

Yeah, sure. I've emailed @rbonthond ... Let's see.

[rbonthond]

Sorry, these pull requests got lost in spam, I've merged it now, and will see how I can add more maintainers to this repository

[rbonthond]

@unitaker feel free to add @timofurer

[untitaker]

done!