Bump gatsby-plugin-sharp from 2.6.19 to 2.6.20

Bumps [gatsby-plugin-sharp](https://github.com/gatsbyjs/gatsby/tree/HEAD/packages/gatsby-plugin-sharp) from 2.6.19 to 2.6.20.
- [Release notes](https://github.com/gatsbyjs/gatsby/releases)
- [Changelog](https://github.com/gatsbyjs/gatsby/blob/master/packages/gatsby-plugin-sharp/CHANGELOG.md)
- [Commits](https://github.com/gatsbyjs/gatsby/commits/gatsby-plugin-sharp@2.6.20/packages/gatsby-plugin-sharp)

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

package.json

@@ -15,7 +15,7 @@
     "gatsby-plugin-remove-serviceworker": "^1.0.0",
     "gatsby-plugin-robots-txt": "^1.5.1",
     "gatsby-plugin-sass": "^2.3.12",
-    "gatsby-plugin-sharp": "^2.6.19",
+    "gatsby-plugin-sharp": "^2.6.20",
     "gatsby-source-filesystem": "^2.3.19",
     "gatsby-transformer-sharp": "^2.5.11",
     "http-status-codes": "^1.4.0",

yarn.lock

@@ -6463,10 +6463,10 @@ gatsby-plugin-sass@^2.3.12:
     "@babel/runtime" "^7.10.3"
     sass-loader "^7.3.1"
 
-gatsby-plugin-sharp@^2.6.19:
-  version "2.6.19"
-  resolved "https://registry.yarnpkg.com/gatsby-plugin-sharp/-/gatsby-plugin-sharp-2.6.19.tgz#027e9a55e44fafff80e1c4c4811242a2fae8d12c"
-  integrity sha512-0SVP2xk8Ml+hml30+oBP/SRm/ztGV6sDOlOUoEHuv6SssxkDcKc9aSScn0qB1HsKGDYDm1gcmDmw48Bq4U78rA==
+gatsby-plugin-sharp@^2.6.20:
+  version "2.6.20"
+  resolved "https://registry.yarnpkg.com/gatsby-plugin-sharp/-/gatsby-plugin-sharp-2.6.20.tgz#c0e5bfb537a8df5be9650544ba8cec65759b366a"
+  integrity sha512-5M6wYzxer+yWEIhq+eE7XwcDWpJqm2Nr6V14UCfbR5KYmYpkEbDVm2dw1raBFonf/XUQ15idYjPp3U0mY6xfAg==
   dependencies:
     "@babel/runtime" "^7.10.3"
     async "^2.6.3"