Update mlblocks cap (#278)

Author: sarahmish

setup.py

@@ -17,7 +17,7 @@
     'iso639>=0.1.4,<0.2',
     'langdetect>=1.0.7,<2',
     'lightfm>=1.15,<2',
-    'mlblocks>=0.4.0.dev0,<0.6',
+    'mlblocks>=0.4.0.dev0,<0.7',
     'networkx>=2.0,<3',
     'nltk>=3.3,<4',
     'numpy<1.21.0,>=1.16.0',