Add missing dependency: markdown

yarn.lock

@@ -168,6 +168,11 @@
   resolved "https://registry.yarnpkg.com/@types/scheduler/-/scheduler-0.16.1.tgz#18845205e86ff0038517aab7a18a62a6b9f71275"
   integrity sha512-EaCxbanVeyxDRTQBkdLb3Bvl/HK7PBK6UJjsSixB0iHKoWxE5uu2Q/DgtpOhPIojN0Zl1whvOd7PoHs2P0s5eA==
 
+abbrev@1:
+  version "1.1.1"
+  resolved "https://registry.yarnpkg.com/abbrev/-/abbrev-1.1.1.tgz#f8f2c887ad10bf67f634f005b6987fed3179aac8"
+  integrity sha512-nne9/IiQ/hzIhY6pdDnbBtz7DjPTKrY00P/zvPSm5pOFkl6xuGrGnXn/VtTNNfNtAfZ9/1RtehkszU9qcTii0Q==
+
 ansi-regex@^5.0.0:
   version "5.0.0"
   resolved "https://registry.yarnpkg.com/ansi-regex/-/ansi-regex-5.0.0.tgz#388539f55179bf39339c81af30a654d69f87cb75"
@@ -627,6 +632,13 @@ lru-queue@^0.1.0:
   dependencies:
     es5-ext "~0.10.2"
 
+markdown@^0.5.0:
+  version "0.5.0"
+  resolved "https://registry.yarnpkg.com/markdown/-/markdown-0.5.0.tgz#28205b565a8ae7592de207463d6637dc182722b2"
+  integrity sha1-KCBbVlqK51kt4gdGPWY33BgnIrI=
+  dependencies:
+    nopt "~2.1.1"
+
 memoizee@^0.4.15:
   version "0.4.15"
   resolved "https://registry.yarnpkg.com/memoizee/-/memoizee-0.4.15.tgz#e6f3d2da863f318d02225391829a6c5956555b72"
@@ -676,6 +688,13 @@ noms@0.0.0:
     inherits "^2.0.1"
     readable-stream "~1.0.31"
 
+nopt@~2.1.1:
+  version "2.1.2"
+  resolved "https://registry.yarnpkg.com/nopt/-/nopt-2.1.2.tgz#6cccd977b80132a07731d6e8ce58c2c8303cf9af"
+  integrity sha1-bMzZd7gBMqB3MdbozljCyDA8+a8=
+  dependencies:
+    abbrev "1"
+
 nth-check@^2.0.0:
   version "2.0.0"
   resolved "https://registry.yarnpkg.com/nth-check/-/nth-check-2.0.0.tgz#1bb4f6dac70072fc313e8c9cd1417b5074c0a125"