2.15.0-rc1

• The HTTP client now allows up to 20 connections to be active at once.
  Previously the limit was 2.
• Update maxmind-db dependency to a new version that no longer uses
  Jackson. This improves database lookup performance.
• The isResidentialProxy() method was added to
  com.maxmind.geoip2.model.AnonymousIpResponse and
  com.maxmind.geoip2.record.Traits for use with the Anonymous IP database
  and GeoIP2 Precision insights.