Add markdown devdependency for build

package.json

@@ -0,0 +1,5 @@
+{
+  "devDependencies": {
+    "markdown": "^0.5.0"
+  }
+}

yarn.lock

@@ -0,0 +1,19 @@
+# THIS IS AN AUTOGENERATED FILE. DO NOT EDIT THIS FILE DIRECTLY.
+# yarn lockfile v1
+
+
+abbrev@1:
+  version "1.1.1"
+  resolved "https://registry.yarnpkg.com/abbrev/-/abbrev-1.1.1.tgz#f8f2c887ad10bf67f634f005b6987fed3179aac8"
+
+markdown@^0.5.0:
+  version "0.5.0"
+  resolved "https://registry.yarnpkg.com/markdown/-/markdown-0.5.0.tgz#28205b565a8ae7592de207463d6637dc182722b2"
+  dependencies:
+    nopt "~2.1.1"
+
+nopt@~2.1.1:
+  version "2.1.2"
+  resolved "https://registry.yarnpkg.com/nopt/-/nopt-2.1.2.tgz#6cccd977b80132a07731d6e8ce58c2c8303cf9af"
+  dependencies:
+    abbrev "1"