Added a V4 KDBX xsd

[maven-release-plugin] copy for tag KeePassJava2-2.1.4

[maven-release-plugin] copy for tag KeePassJava2-2.1.3

[maven-release-plugin] copy for tag KeePassJava2-2.1.2

[maven-release-plugin] copy for tag KeePassJava2-2.1.1

[maven-release-plugin] copy for tag KeePassJava2-2.1.0

[maven-release-plugin] copy for tag keepassjava2-2.0.1

[maven-release-plugin] copy for tag keepassjava2-2.0.0