Correct version in CHANGELOG to 0.0.2

The most recent release was 0.0.2. Fix the changelog to reflect this.

This was introduced in ce215ef335ff07bff1ecd2754061db14723c649a
following the confusion corrected by
031c81d1f17cf0416043367957d85af4513493c0.
Merge pull request #14 from alphagov/fix-changelog-ver

Correct version in CHANGELOG to 0.0.2