Add optional stream argument to render to

[joshwlewis]

As mentioned in SamVerschueren/listr-update-renderer#26, it makes sense to send human-readable and informational logging to stderr when designing a pipeable command. Those commands typically reserve stdout for data that could be sent to another command. This PR attempts to make this renderer useful in that scenario by adding an optional argument to send output to streams other than process.stdout, like process.stderr.