Republish to npm as snowplow-tracker 0.1.1

[alexanderdean]

There was some bad pilot error on my part:

• I accidentally published snowplow-javascript-tracker to npm, because this ticket hasn't been actioned yet: Prevent accidental publication of snowplow-tracker to npm snowplow/snowplow-javascript-tracker#300
• I reviewed https://www.npmjs.com/package/snowplow-tracker, saw two versions (2.2.0 and 0.1.0), and mistakenly identified 0.1.0 as another accidental publication of the snowplow-javascript-tracker, rather than the original release of the snowplow-nodejs-tracker to npm
• I erroneously completely unpublished snowplow-tracker from npm, breaking the dependency for any users

I cannot re-publish 0.1.0 (npm rules), and therefore will re-publish as 0.1.1 instead.

Note also that we will have to skip version 2.2.0, placeholder ticket to remind us of that: #11