Release v5.2.0

This release contains the following updates:

• Move code packages and maven groupdId from com.bettercloud to io.github.jopenlibs. (PR #2)
• Fix and refactoring data wrapping, add integration tests with the last Vault version (vault 1.11.4). (PR #4), (PR #17)
• Upgrade tests dependencies. (PR #11)
• Port the patch of Ian Ferguson that includes X-Vault-Request: true header on all requests to work with Vault Agent's w/ require_request_header set to true. (PR #16)