Bump image-size from 0.8.3 to 0.9.1

Bumps [image-size](https://github.com/image-size/image-size) from 0.8.3 to 0.9.1.
- [Release notes](https://github.com/image-size/image-size/releases)
- [Commits](image-size/image-size@v0.8.3...v0.9.1)

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

Author: dependabot[bot]

package.json

@@ -81,7 +81,7 @@
     "express": "^4.16.3",
     "extract-text-webpack-plugin": "^4.0.0-beta.0",
     "get-pixels": "^3.3.0",
-    "image-size": "^0.8.3",
+    "image-size": "^0.9.1",
     "istanbul": "^0.4.5",
     "jasmine-core": "^3.5.0",
     "jsdoc": "^3.6.3",