Rename resolve_type method

[jkimbo]

Fixes #50

[syrusakbary]

I like this, however, let's make sure we write this down as a breaking change on the release, so people are aware the name has to be changed from resolve_type to _resolve_type.
(It will also require a minor version bump 2.2.0)

[honi]

Any update on this?

[mvanlonden]

Approving but wait until ready for 3.0 release, should be merged alongside #738

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[jkimbo]

For completeness the decision was taken to not make this change for the following reasons:

1. the workaround for it is quite easy:

class MyInterface(Interface):
    type_ = String(name="type")
    def resolve_type_(_, info):
        return "foo"

2. _resolve_type is a bit ugly

3. I think we should be moving towards a @field decorator syntax for fields + resolvers. I’ve been using it my latest project and I quite like it.