Add optional=true

[maven-release-plugin] copy for tag parent-1.11

[maven-release-plugin] copy for tag parent-1.10

[maven-release-plugin] copy for tag parent-1.9

[maven-release-plugin] copy for tag parent-1.8

[maven-release-plugin] copy for tag kerberos-sso-1.7

[maven-release-plugin] copy for tag kerberos-sso-1.6

[maven-release-plugin] copy for tag kerberos-sso-1.5

[maven-release-plugin] copy for tag kerberos-sso-1.4

[maven-release-plugin] copy for tag kerberos-sso-1.3