chore(deps-dev): bump gatsby-plugin-sass from 2.1.17 to 2.1.18 in /www

Bumps [gatsby-plugin-sass](https://github.com/gatsbyjs/gatsby/tree/HEAD/packages/gatsby-plugin-sass) from 2.1.17 to 2.1.18. - [Release notes](https://github.com/gatsbyjs/gatsby/releases) - [Changelog](https://github.com/gatsbyjs/gatsby/blob/master/packages/gatsby-plugin-sass/CHANGELOG.md) - [Commits](https://github.com/gatsbyjs/gatsby/commits/gatsby-plugin-sass@2.1.18/packages/gatsby-plugin-sass) Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Author: dependabot-preview[bot]

www/package.json

@@ -22,7 +22,7 @@
  "gatsby-plugin-css-literal-loader": "^1.0.0",
  "gatsby-plugin-emotion": "^4.1.10",
  "gatsby-plugin-less": "^3.0.9",
- "gatsby-plugin-sass": "^2.1.17",
+ "gatsby-plugin-sass": "^2.1.18",
  "gatsby-plugin-sorted-assets": "^1.0.2",
  "gatsby-remark-prismjs": "^3.3.17",
  "gatsby-source-filesystem": "2.1.30",

www/yarn.lock

@@ -5030,12 +5030,12 @@ gatsby-plugin-page-creator@^2.1.25:
  lodash "^4.17.15"
  micromatch "^3.1.10"
 
-gatsby-plugin-sass@^2.1.17:
- version "2.1.17"
- resolved "https://registry.yarnpkg.com/gatsby-plugin-sass/-/gatsby-plugin-sass-2.1.17.tgz#0c0735f9c61601a80ebb14a5f286b8d90e643b03"
- integrity sha512-SiCbX2RH1WpQOIdnljLviV5N94wmDZoqEPZlTbZinr0TePYOLMVu5Wio/yEZm9sFzVeEpkxQt3AeKaMozsyOIw==
+gatsby-plugin-sass@^2.1.18:
+ version "2.1.18"
+ resolved "https://registry.yarnpkg.com/gatsby-plugin-sass/-/gatsby-plugin-sass-2.1.18.tgz#b9acbe994a79aa96b7595943c8292f81b0b4d9f8"
+ integrity sha512-NOpFUX7eX1DoSzNI51GV5s1nYFmWFkbL85P9CWExQM23r8gDT6Kdv1Rgj8WZ1wwq/Bmr6UnJxFGy5PawBCaR1g==
  dependencies:
- "@babel/runtime" "^7.6.2"
+ "@babel/runtime" "^7.6.3"
  sass-loader "^7.3.1"
 
 gatsby-plugin-sorted-assets@^1.0.2: