Version 0.13.0

ADD #1100: Provide access to the callbacks of SMAC.
ADD #1185: New leaderboard functionality to visualize models
FIX #1133: Refer to the correct attribute in an error message.
FIX #1154: Allow running Auto-sklearn on a 32-bit system.
MAINT #924: Instead of passing classes for the resampling strategy one has now to pass objects.
MAINT #1108: Limit the number of threads used by numpy and/or scikit-learn via threadpoolctl.
MAINT #1135: Simplify internal workflow of pandas handling. This results in pandas being passed directly passed to scikit-learn models instead of being internally converted into a numpy array. However, this should neither impact the behavior nor the performance of Auto-sklearn.
MAINT #1157: Drop support for Python 3.6, enable support for Python 3.9.
MAINT #1159: Remove the output directory argument to the classifier and regressor. Despite the name, the output directory was not used and was a leftover from participating in the AutoML challenges.
MAINT #1187: Bump requires SMAC version to at least 0.14.
DOC #1109: Add an FAQ.
DOC #1126: Add new examples on how to use scikit-learn's inspect module.
DOC #1136: Add a new example on how to perform multi-output regression.
DOC #1152: Enable link checking when buiding the documentation.
DOC #1158: New example on how to configure the logger for Auto-sklearn.
DOC #1165: Improve the readme page.

Contributors v0.13.0