Add Shipkit integration for Bintray deployment

[csgregorian]

Shipkit setup for Bintray deployment, requires env vars and probably some other config changes.

[xkrogen]

Based on https://github.com/mockito/shipkit/blob/master/docs/getting-started.md#initializing-shipkit , it sounds like there should be a version.properties file?

Let's make sure we do a test run as described here: https://github.com/mockito/shipkit/blob/master/docs/getting-started.md#test-run

[csgregorian]

Fixed up: can't do a test yet without the requisite Github and Bintray keys.

[xkrogen]

Have we tried uploading to the shipkit-bootstrap repo for testing as described in the ShipKit getting started docs? https://github.com/mockito/shipkit/blob/master/docs/getting-started.md#test-run

[xkrogen]

I set up the TravisCI repo settings to have the necessary keys. But please let's do a test push as described in the ShipKit setup before committing this.

[csgregorian]

Only took 17 tries: https://github.com/csgregorian/dynamometer/releases/tag/v0.1.17

[xkrogen]

Cool! Is there anything I should be aware of to prevent it from taking 17 tries on the real repository? 😄

I took a look through the files that got added: https://bintray.com/version/files/shipkit-bootstrap/bootstrap/maven/0.1.17?order=asc&sort=name&basePath=com%2Flinkedin%2Fdynamometer&tab=files
And I found that all of the JARs are present, but not the distribution tarball. We can leave that out for now, but in a follow-up, let's try to get the tarball up there as well. I think we need to follow the instructions here: https://github.com/bintray/gradle-bintray-plugin#step-7-define-artifacts-to-be-uploaded-to-bintray

[csgregorian]

tl;dr things that (probably) won't make a difference in CI

• I had to change it to point at my local fork instead of linkedin/dynamometer because it was trying to make release notes.
• I did end up having to create a Github write auth token contrary to the instructions because it was trying to create release notes: might be because I have my repos cloned as git:// instead of https:// and it wouldn't prompt for a user/pass, not sure 🤷‍♂️
• Also had to delete the previous_version line from version.properties every time it failed, because the release failing wouldn't prevent it from incrementing the version number, and then the next time it would fail because it couldn't find the previous_version release 🤦‍♂️

[xkrogen]

LGTM. Let's see how it goes!