docs(gatsby-plugin-preload-fonts): add external chrome env var (gatsbyjs#21845)

nibtime · wardpeet · web-flow · commit 8256fd42c732 · 2020-02-29T12:56:58.000+01:00
Co-authored-by: Ward Peeters &lt;ward@coding-tech.com&gt;
diff --git a/packages/gatsby-plugin-preload-fonts/README.md b/packages/gatsby-plugin-preload-fonts/README.md
@@ -137,3 +137,6 @@ npm run preload-fonts -- --no-sandbox
 
 This comes with [inherent security risks](https://chromium.googlesource.com/chromium/src/+/master/docs/linux_suid_sandbox_development.md),
 but you should be alright since you're only running it locally.
+
+### Use different Chrome/Chromium executable
+In some cases, you might have to point Puppeteer to an external installation of Chrome/Chromium (e.g., on Alpine Linux, the build-in version of Chromium does not work). You can set the `PUPPETEER_EXECUTABLE_PATH` environment variable to the path of your custom chromium installation. A list with all environment variables to configure Puppeteer can be found [at the official docs](https://pptr.dev/#?product=Puppeteer&version=v1.20.0&show=api-environment-variables).
