Bump @rollup/plugin-babel from 5.2.1 to 5.3.0 in /token-swap/js

Bumps [@rollup/plugin-babel](https://github.com/rollup/plugins) from 5.2.1 to 5.3.0.
- [Release notes](https://github.com/rollup/plugins/releases)
- [Commits](rollup/plugins@babel-v5.2.1...babel-v5.3.0)

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