Merge pull request RasaHQ#5609 from RasaHQ/dependabot/pip/matplotlib-3.2.1

Bump matplotlib from 3.1.3 to 3.2.1

Author: tmbo

poetry.lock

@@ -67,7 +67,7 @@ showcontent = false
 python = "^3.6"
 boto3 = "^1.12"
 requests = "^2.23"
-matplotlib = "~3.1"
+matplotlib = ">=3.1,<3.3"
 attrs = "~19.3"
 jsonpickle = "~1.3"
 redis = "^3.4"