build(scripts): add missing rimraf dependency
build(scripts): add missing rimraf dependency

It looks like we were a little hasty in #492 as rimraf is used directly
within package.json in the `flow-typed` script and so it needs to remain
as a dev dependency.

See https://github.com/LN-Zap/zap-desktop/pull/492

LN-Zap/zap-desktop,LN-Zap/zap-desktop,LN-Zap/zap-desktop