Update dependencies (credentials, mailer, promoted-builds, etc.)

bridge-method-annotation - 1.12 to 1.13
credentials - 1.15 to 1.16.1
ssh-credentials - 1.7.1 to 1.9
matrix-project - 1.2 to 1.3
mailer - 1.9 to 1.11
[maven-release-plugin] prepare release git-2.3-beta-2
[maven-release-plugin] prepare for next development iteration