Upgrade stencil-cli to handlebars v4

[flyingL123]

Are there any plans to update the version of handlebars that stencil-cli uses? In v4, handlebars made changes to how context changes with certain block helpers.

I'm using handlebars on the client-side, and it's nice to be able to share templates between the client and server. However, using v4 on the client causes issues since the number of ../ uses within blocks needs to be different for v3 on the sever, and v4 on the client.

See "Compatibility notes" here: https://github.com/wycats/handlebars.js/blob/master/release-notes.md#v400---september-1st-2015

And handlebars-lang/handlebars.js#1028

[diztinct-glenn]

I reckon this can be marked closed now, no?

[dannydulai]

how does one enable v4?