Merge pull request RasaHQ#5653 from RasaHQ/dependabot/pip/nbsphinx-0.6.0

Bump nbsphinx from 0.5.1 to 0.6.0

Author: alwx

poetry.lock

@@ -132,7 +132,7 @@ pytest-xdist = "^1.31.0"
 pytest = "^5.3.4"
 freezegun = "^0.3.14"
 responses = "^0.10.9"
-nbsphinx = "~0.5"
+nbsphinx = "~0.6"
 aioresponses = "^0.6.2"
 moto = "==1.3.14"
 fakeredis = "^1.4.0"