DOC: unicode error references correct issue

Author: tswast

docs/source/changelog.rst

@@ -4,7 +4,7 @@ Changelog
 0.3.1 / 2018-02-13
 ------------------
 
-- Fix an issue where Unicode couldn't be uploaded in Python 2 (:issue:`93`)
+- Fix an issue where Unicode couldn't be uploaded in Python 2 (:issue:`106`)
 - Add support for a passed schema in :func:``to_gbq`` instead inferring the schema from the passed ``DataFrame`` with ``DataFrame.dtypes`` (:issue:`46`)
 - Fix an issue where a dataframe containing both integer and floating point columns could not be uploaded with ``to_gbq`` (:issue:`116`)
 - ``to_gbq`` now uses ``to_csv`` to avoid manually looping over rows in a dataframe (should result in faster table uploads) (:issue:`96`)