Support Deno v1.4

[ryo-ma]

Thank you for the good product.
Will you support Deno version 1.4?

[Nathan Rajlich]

I'll update the default version shortly, but note that you can configure a specific version by setting the DENO_VERSION build env var in your project's configuration.

[Nathan Rajlich]

v0.7.1 uses Deno 1.4.1 by default.

[ryo-ma]

Thanks!