Flaky threaded parallelism unit test
We saw `test_score_pipelines_passes_X_train_y_train[multiclass-cf_threaded]` flake on the linux nightlies on 2021-10-27.

Logs are [here](https://github.com/alteryx/evalml/runs/4018971157?check_suite_focus=true)

We've seen this flake a couple of times (@angela97lin saw it fail on her PR once) so we're recording it here to see how widespread the problem is.

Although this is similar to #2669, that issue tracks figuring out why the process-based parallelism tests (now removed) used to flake.

Closing out this issue involves figuring out why this test can flake and proposing a fix if possible. 
diff --git a/docs/source/release_notes.rst b/docs/source/release_notes.rst
index 00fe9625..28637adf 100644
--- a/docs/source/release_notes.rst
+++ b/docs/source/release_notes.rst
@@ -1,6 +1,18 @@
 ﻿Release Notes
 -------------
 **Future Releases**
+    * Enhancements
+    * Fixes
+    * Changes
+    * Documentation Changes
+    * Testing Changes
+
+.. warning::
+
+    **Breaking Changes**
+
+
+**v0.42.0 Jan. 18, 2022**
     * Enhancements
         * Required the separation of training and test data by ``gap`` + 1 units to be verified by ``time_index`` for time series problems :pr:`3208`
         * Added support for boolean features for ``ARIMARegressor`` :pr:`3187`
diff --git a/evalml/__init__.py b/evalml/__init__.py
index fa740e0e..0ae8248f 100644
--- a/evalml/__init__.py
+++ b/evalml/__init__.py
@@ -23,4 +23,4 @@ with warnings.catch_warnings():
 warnings.filterwarnings("ignore", category=FutureWarning)
 warnings.filterwarnings("ignore", category=DeprecationWarning)
 
-__version__ = "0.41.0"
+__version__ = "0.42.0"
diff --git a/setup.py b/setup.py
index a22680a7..4f274d64 100644
--- a/setup.py
+++ b/setup.py
@@ -11,7 +11,7 @@ extras_require['complete'] = sorted(set(sum(extras_require.values(), [])))
 
 setup(
     name='evalml',
-    version='0.41.0',
+    version='0.42.0',
     author='Alteryx, Inc.',
     author_email='support@featurelabs.com',
     description='EvalML is an AutoML library that builds, optimizes, and evaluates machine learning pipelines using domain-specific objective functions.',
['setup.py', 'evalml/__init__.py', 'docs/source/release_notes.rst']