Bump node-sass from 4.7.2 to 4.9.0

Bumps [node-sass](https://github.com/sass/node-sass) from 4.7.2 to 4.9.0.
- [Release notes](https://github.com/sass/node-sass/releases)
- [Changelog](https://github.com/sass/node-sass/blob/master/CHANGELOG.md)
- [Commits](sass/node-sass@v4.7.2...v4.9.0)

Signed-off-by: dependabot[bot] <support@dependabot.com>

Author: dependabot-support

package.json

@@ -89,7 +89,7 @@
     "mime": "^2.3.1",
     "mongoose": "~4.13.2",
     "multer": "~1.3.0",
-    "node-sass": "~4.7.2",
+    "node-sass": "~4.9.0",
     "quill-url-embeds": "^1.2.5",
     "raven": "~2.6.1",
     "request": "~2.86.0",

yarn.lock

@@ -3583,11 +3583,7 @@ mute-stream@0.0.7:
   version "0.0.7"
   resolved "https://registry.yarnpkg.com/mute-stream/-/mute-stream-0.0.7.tgz#3075ce93bc21b8fab43e1bc4da7e8115ed1e7bab"
 
-nan@^2.3.2:
-  version "2.8.0"
-  resolved "https://registry.yarnpkg.com/nan/-/nan-2.8.0.tgz#ed715f3fe9de02b57a5e6252d90a96675e1f085a"
-
-nan@^2.9.2:
+nan@^2.10.0, nan@^2.9.2:
   version "2.10.0"
   resolved "https://registry.yarnpkg.com/nan/-/nan-2.10.0.tgz#96d0cd610ebd58d4b4de9cc0c6828cda99c7548f"
 
@@ -3660,9 +3656,9 @@ node-pre-gyp@^0.9.0:
     semver "^5.3.0"
     tar "^4"
 
-node-sass@~4.7.2:
-  version "4.7.2"
-  resolved "https://registry.yarnpkg.com/node-sass/-/node-sass-4.7.2.tgz#9366778ba1469eb01438a9e8592f4262bcb6794e"
+node-sass@~4.9.0:
+  version "4.9.0"
+  resolved "https://registry.yarnpkg.com/node-sass/-/node-sass-4.9.0.tgz#d1b8aa855d98ed684d6848db929a20771cc2ae52"
   dependencies:
     async-foreach "^0.1.3"
     chalk "^1.1.1"
@@ -3676,7 +3672,7 @@ node-sass@~4.7.2:
     lodash.mergewith "^4.6.0"
     meow "^3.7.0"
     mkdirp "^0.5.1"
-    nan "^2.3.2"
+    nan "^2.10.0"
     node-gyp "^3.3.1"
     npmlog "^4.0.0"
     request "~2.79.0"