upgrade dependencies

[ccleung]

Need to upgrade dependencies for this gem, or else there will be a gem conflict with other public gems, e.g., latest google-cloud-storage requires faraday ~> 0.11 in it's chain of dependencies:

google-cloud-storage (~> 1.1) was resolved to 1.1.0, which depends on
      google-cloud-core (~> 1.0) was resolved to 1.0.0, which depends on
        google-cloud-env (~> 1.0) was resolved to 1.0.0, which depends on
          faraday (~> 0.11)

Issue: 622a19a Looks to have been resolved by ruby-oauth/oauth2#271 so we can remove the restriction on oauth2 dependency lock

[Edouard-chin]

Let's remove this dependency, we can let omniauth-oauth2 resolve it. It was added only because v1.2.0 of oauth2 introduced an issue on encoding which was later fixed by ruby-oauth/oauth2#271

[Edouard-chin]

omniauth/omniauth-oauth2@v1.2.0...v1.4.0

The change from 1.2.0 to 1.4.0 looks safe to me but we might need to loose ruby 2.1 support. Not sure how many app which are on 2.1 still uses that gem

[ccleung]

updated to lock this version to depend on 2.1.9 and greater, mirroring omniauth gem's requirements https://rubygems.org/gems/omniauth

[ccleung]

i think travis ruby versions may need to be updated to test ruby >= 2.1.9

[Edouard-chin]

Let's modify travis rvm and should be good

https://github.com/Shopify/omniauth-shopify-oauth2/blob/master/.travis.yml#L3

[ccleung]

updated, thanks for the feedback!

[JoePym]

What's the plan to bump the version of the gem? I feel given as we are deprecating support for a patch ruby version, we should bump the patch level of the gem.

[ccleung]

@JoePym we should do a major bump i think, since it's a breaking backwards incompatible change with certain ruby versions?

[ccleung]

we will do a minor version bump for this as per discussion