API response should return OMG network version

[pnowosie]

Standard response schema from the API (Watcher & ch-ch) consist of version field, set to 1.0. We agreed the version means OMG network version.

From the other side there is EIP712Domain structure - part of EIP-712 structural signing proposal, which contains the version field as well.

It could be beneficial that API response will present appropriate network version.

However I'd like to put into discussion the fact that change in EIP712Domain requires contract redeployment (invalidates all previous signatures). This means that API response would not follow release tags (Samrong is now v0.2.1, API responses would show version: "0.2")

What's your point on :point_up: @Pongch @kevsul @kasima @pdobacz :question:

[kasima]

We'll match up the EIP-712 Domain version in the next Network Upgrade and we'll keep that matched to the minor version until we reach the major version.

In the meantime, let's merge #770 to v0.2 branch and port it to master.

[pnowosie]

@kasima I've created #810 to master was v0.2 cut yet or my change will eventually appear in v0.2.x :question:

[kasima]

Please port it to v0.2 branch (may be a fast-forward) and when a release happens, cut the v0.2.2 tag.