GO and tchannel-go version update

• Updated Go to v1.16.6.
• Updated tchannel-go to v1.32.0.

Add NodeOverride option

• Adds NodeOverride option to enable overriding the default SWIM-based gossip-style node membership protocol used for membership management (#224).
• Other housekeeping changes for repository health including migrating to Github Actions (#223, #227).

Ordered hashring.LookupN; router.GetNClients; sirupsen/logrus import fix

• Fix: LookupN returns ring node destinations in ring order #211
• Fix: Use lower case sirupsen/logrus import #208
• Feature: Added GetNClients to router #212

Allow requiresAppInPing to be configured

Merge pull request #209 from uber/add_opt

Allow RequiresAppInPing to be configured

Add option to enforce identical app name in pings

Merge pull request #206 from uber/enforce_app

Add option to enforce identical app name in pings