Bump gatsby-image from 2.2.20 to 2.2.21

Bumps [gatsby-image](https://github.com/gatsbyjs/gatsby/tree/HEAD/packages/gatsby-image) from 2.2.20 to 2.2.21.
- [Release notes](https://github.com/gatsbyjs/gatsby/releases)
- [Changelog](https://github.com/gatsbyjs/gatsby/blob/master/packages/gatsby-image/CHANGELOG.md)
- [Commits](https://github.com/gatsbyjs/gatsby/commits/gatsby-image@2.2.21/packages/gatsby-image)

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

Author: dependabot-preview[bot]

package.json

@@ -7,7 +7,7 @@
   "dependencies": {
     "classnames": "^2.2.6",
     "gatsby": "^2.15.21",
-    "gatsby-image": "^2.2.20",
+    "gatsby-image": "^2.2.21",
     "gatsby-plugin-manifest": "^2.2.18",
     "gatsby-plugin-offline": "^3.0.8",
     "gatsby-plugin-postcss": "^2.1.8",

yarn.lock

@@ -5123,10 +5123,10 @@ gatsby-graphiql-explorer@^0.2.18:
   dependencies:
     "@babel/runtime" "^7.6.0"
 
-gatsby-image@^2.2.20:
-  version "2.2.20"
-  resolved "https://registry.yarnpkg.com/gatsby-image/-/gatsby-image-2.2.20.tgz#df156fcc8ee166954e7f56a93729569f05a50624"
-  integrity sha512-bf2YnqJLYmUnXkXjVF20I6x09rOJS3UrFKoWLvmsZUvYSunGjFda0SvE05nTFCc/7PGvlGhua/NZMNtXb5glmA==
+gatsby-image@^2.2.21:
+  version "2.2.21"
+  resolved "https://registry.yarnpkg.com/gatsby-image/-/gatsby-image-2.2.21.tgz#8db72cf42571c8c4ef24bc5a71a20376e67d0208"
+  integrity sha512-ejslqo/aYs9cy7brYdJPB3PdpPO40BXC9jmhiObSQ49hLpSj4D02tBJOtrX3PPdSEsLZ0wTSWTTSEuxJWXOy+Q==
   dependencies:
     "@babel/runtime" "^7.6.0"
     object-fit-images "^3.2.4"