Bump acorn from 6.4.0 to 6.4.1 in /demo (#158)

Bumps [acorn](https://github.com/acornjs/acorn) from 6.4.0 to 6.4.1.
- [Release notes](https://github.com/acornjs/acorn/releases)
- [Commits](https://github.com/acornjs/acorn/compare/6.4.0...6.4.1)

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

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

demo/yarn.lock

   integrity sha1-Ejy487hMIXHx9/slJhWxx4prGow=
 
 acorn@^6.0.1:
-  version "6.4.0"
-  resolved "https://nexus.bybutter.com/repository/npm-group/acorn/-/acorn-6.4.0.tgz#b659d2ffbafa24baf5db1cdbb2c94a983ecd2784"
-  integrity sha1-tlnS/7r6JLr12xzbsslKmD7NJ4Q=
+  version "6.4.1"
+  resolved "https://registry.yarnpkg.com/acorn/-/acorn-6.4.1.tgz#531e58ba3f51b9dacb9a6646ca4debf5b14ca474"
+  integrity sha512-ZVA9k326Nwrj3Cj9jlh3wGFutC2ZornPNARZwsNYqQYgN0EsV2d53w5RN/co65Ohn4sUAUtb1rSUAOD6XN9idA==
 
 acorn@^7.1.0:
   version "7.1.0"
   integrity sha1-LMD+D7p0LZf9UnxCoTvsTusGJBw=
 
 react-native-autoheight-webview@../:
-  version "1.4.1"
+  version "1.4.2"
   dependencies:
     prop-types "^15.7.2"