feat: add deno target to rollup build script

[lsh]

This is a proof of concept to display a working build for #280.

Currently the Arquero distribution on Skypack does not work with Deno. This PR allows a cursory look into adding Deno as a distribution target. To see it in use, build Arquero normally (yarn build), then in a Deno REPL (assuming the current working directory is Arquero's root):

const aq = await import('./dists/arquero.deno.js');

[domoritz]

Suggested change

	values: { 'apache-arrow': 'https://cdn.skypack.dev/[email protected]' },
	values: { 'apache-arrow': 'https://cdn.jsdelivr.net/npm/[email protected]/+esm' },

Note that this means arguer needs #277, I think.

[jheer]

Closing out due to the age of the PR and its draft status. But I'd be happy to consider an updated PR for a Deno build on top of Arquero v6 (#358)!