Include Bootstrap minor version in packaging name

[twagoo]

Suggested by @andmor-: include the minor version of bootstrap in the packaging name through the classifier name.

So e.g.:
base-style-0.2.0-css-with-bootstrap.jar
-> base-style-0.2.0-css-with-bootstrap-3.3.x.jar

base-style-0.2.0-less-with-bootstrap.jar
-> base-style-0.2.0-less-with-bootstrap-3.3.x.jar

base-style-0.2.0-less-without-bootstrap.jar
-> base-style-0.2.0-less-without-bootstrap-3.3.x.jar