Bumps ch.qos.logback:logback-classic from 1.5.20 to 1.5.22.

• 572379a prepare release 1.5.22
• 39d17ea fix status printing of variable substitution when the variable name contains ...
• 75509a9 fix PR 404, LOGBACK-543
• 8eb9356 remove unused import
• 6131a3a use a slightly more sophisticated guard for printing status messages
• 9efca21 add no-args constructor to support various serialization frameworks
• 1bea580 minor comment edits
• bd07fdd update angus, greenmail versions
• aef993c start work on 1.5.22-SNAPSHOT
• fed6f37 prepare release 1.5.21
• Additional commits viewable in compare view