Update stapler (1.208-SNAPSHOT -> 1.209) to fix Maven build

Skipped 1.208(-SNAPSHOT)? since it seems to not deployed to http://repo.jenkins-ci.org
by the problem of Maven configuration at SHA1@03c56ad8c976083d9526f56a21640e6b0c0bc14b
Merge pull request #81 from yyuu/fix-maven-build

Fix unresolvable dependency of stapler 1.208-SNAPSHOT