Log Message:
Update to 0.2.1

Upstream changes:
rlang 0.2.1
This is a maintenance release that fixes several tidy evaluation issues.

Functions with tidy dots support now allow splicing atomic vectors.

Quosures no longer capture the current srcref.

Formulas are now evaluated in the correct environment by eval_tidy(). This fixes \ 
issues in dplyr and other tidy-evaluation interfaces.