Allow addition <tag> formats

[seancorfield]

Currently, depstar assumes the <tag> in pom.xml is the version with a prefix of v but people use lots of different conventions. @dharrigan mentioned this on Slack, that he uses just the version number.

A replacement like this could be used:

(str/replace-first "<project><scm><tag>clojure-1.2.3</tag>" #"<tag>([^<]*)1.2.3</tag>" "<tag>$11.2.4</tag>")

This means the version portion needs to be regex-quoted \\Q...\\E. Or use java.util.regex.Pattern/quote