DataDog::DogStatsd versions through 0.07 for Perl allow metric injections from event tags

DataDog::DogStatsd versions through 0.07 for Perl allow metric injections from event tags.

DataDog::DogStatsd does not properly sanitise input, allowing metric injections of data from untrusted sources.

The format_event method (used by the event method) does not validate the content of the tags, which may contain commas (allowing tags to be injected) or newlines, pipes and colons that allow metric injections. (There is an ineffective s/|//g to remove pipes, but because the pipe is not escaped, it is interpreted as a regular expression metacharacter and has no effect.)