ENUM type should be integer

[merdosy]

When running on protobuf examples, it was failing to create the schema because enums are integers, not strings. With this change, I was able to create the schema properly.

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[merdosy]

I signed it!

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[yugui]

Thank you for your contribution.

Although I understand that there are such use-cases which need to marshal enums into integers, I would like to accept this PR in a bit different way.
So how about adding a runtime option to change the behavior of the plugin? Also, if you want to statically keep the type mapping in your proto file, you can use #6.

This is because of several reasons:

• Strings are also a valid way of marshaling enums. Actually the JSON representation of enums depends on the configuration of the Marshaler --
  https://godoc.org/github.com/golang/protobuf/jsonpb#Marshaler.
• I would like to keep backward compatibility.

[mescanne]

Michael -- we're looking to start maintaining this repo again. Unless you say otherwise, I'm going to assume this pullrequest should be closed.

[judahrand]

Michael -- we're looking to start maintaining this repo again. Unless you say otherwise, I'm going to assume this pullrequest should be closed.

Is this repo now considered actively maintained?

[mescanne]

Michael -- we're looking to start maintaining this repo again. Unless you say otherwise, I'm going to assume this pullrequest should be closed.

Is this repo now considered actively maintained?

Judah - to be clear, there's no allocated budget in Google to maintain this repo. But I'm doing a bit here and there (as necessary) as part of my day job to review PRs, make fixes, etc. It's on a best effort basis.

As always with open source, you're free to fork the repo (as chuhlomin did).

Mark