CircleCI config includes failing publish step to Bintray

[tabboud]

The current CircleCI config includes a publish step to Bintray for all tagged builds which is no longer supported. In addition, the conjure-go os-arch-bin distribution is not used given godel-conjure-plugin vendors this library directly to invoke the code generation.

All recent tagged builds end up failing due to this publish step:

• https://app.circleci.com/pipelines/github/palantir/conjure-go/911/workflows/c8628742-ad2e-4fb9-a384-35d25f3021ea
• https://app.circleci.com/pipelines/github/palantir/conjure-go/945/workflows/86cc3197-db2e-4eb2-9dd9-c8e3a85dc377

Rather than try to publish to Bintray, we should instead switch this project over to use Github actions to publish to Github releases as done by other OSS projects. The resolvers have already been updated to support this, but the publishing code has not yet been updated.