Bump acorn from 6.3.0 to 6.4.1 in /beacon/wasm
Bumps [acorn](https://github.com/acornjs/acorn) from 6.3.0 to 6.4.1.
- [Release notes](https://github.com/acornjs/acorn/releases)
- [Commits](https://github.com/acornjs/acorn/compare/6.3.0...6.4.1)
Signed-off-by: dependabot[bot] <[email protected]>