Update moment from 2.19.0 to 2.19.1 in addons/knobs

[dependencies]

moment has been updated to 2.19.1 in addons/knobs by dependencies.io

2.19.1

• Release Oct 11, 2017

Make react native and webpack both work

• Don't copy license anymore since lerna 3 does it #4225 FIX up the README a bit #4226 Log network location of Storybook app on startup #4232

[codecov]

Codecov Report

Merging #2026 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #2026   +/-   ##
=======================================
  Coverage   21.34%   21.34%           
=======================================
  Files         262      262           
  Lines        5767     5767           
  Branches      695      701    +6     
=======================================
  Hits         1231     1231           
+ Misses       4005     3991   -14     
- Partials      531      545   +14

Impacted Files	Coverage Δ
lib/ui/src/modules/ui/containers/down_panel.js	23.52% <0%> (ø)	⬆️
.../src/manager/containers/CommentsPanel/dataStore.js	34.97% <0%> (ø)	⬆️
...es__/update-addon-info/update-addon-info.output.js	0% <0%> (ø)	⬆️
addons/knobs/src/components/PropForm.js	8.51% <0%> (ø)	⬆️
lib/components/src/navigation/menu_link.js	0% <0%> (ø)	⬆️
...ponents/left_panel/stories_tree/tree_decorators.js	33.33% <0%> (ø)	⬆️
app/react/src/client/preview/element_check.js	41.17% <0%> (ø)	⬆️
app/react/src/client/preview/error_display.js	0% <0%> (ø)	⬆️
addons/knobs/src/KnobManager.js	32% <0%> (ø)	⬆️
addons/info/src/components/markdown/htags.js	30% <0%> (ø)	⬆️
... and 18 more

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[danielduan]

2.19.0 is broken so we should definitely require 2.19.1

[danielduan]

fixes #2006