chore(ci): make CircleCI perform the `mvn deploy` step upon tagged commit on master branch

[aseure]

This commit adds an extra step to the CircleCI configuration to release the project to Bintray if and only if the CI is passing on a semver tagged commit from master and all tests are passing.

In essence, it prevents the releaser to locally configure Maven and fetch credentials and let CircleCI perform the mvn deploy on its own.

You can find extra configuration information from the official CircleCI blog at this address: https://circleci.com/blog/optimizing-maven-builds-on-circleci/