API/ENH: QIIME now depends on BIOM 2.1

QIIME should now depend on BIOM 2.1 and not in BIOM 2.0.1-dev, a note
has been added to the ChangeLog.md file.

Fixes #1590
Merge pull request #1654 from ElDeveloper/biom-2.1

API/ENH: QIIME now depends on BIOM 2.1