bump gatsby-plugin-sass from 6.12.0 to 6.12.3 (#905)

---
updated-dependencies:
- dependency-name: gatsby-plugin-sass
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

package.json

@@ -32,7 +32,7 @@
  "gatsby-plugin-offline": "^6.12.0",
  "gatsby-plugin-react-i18next": "^2.0.5",
  "gatsby-plugin-react-svg": "^3.3.0",
- "gatsby-plugin-sass": "^6.12.0",
+ "gatsby-plugin-sass": "^6.12.3",
  "gatsby-plugin-sharp": "^5.12.0",
  "gatsby-plugin-sitemap": "^6.11.0",
  "gatsby-remark-autolink-headers": "^6.11.0",