Set Dockerfile version label to match cookbook version [skip ci]

Author: LevonBecker

Dockerfile

@@ -9,7 +9,7 @@ ARG chef_role=base
 ARG chef_environment=bonusbits_base
 ARG chef_config_path=/opt/chef-repo
 
-LABEL version="2.1.1" \
+LABEL version="2.1.5" \
       description="Amazon Linux Image built from bonusbits_base cookbook." \
       github="https://github.com/bonusbits/bonusbits_base" \
       website="https://www.bonusbits.com"