Support LiveView 0.19

[Zek]

Getting this dependency error when trying to update to LiveView 0.19:

Because your app depends on live_svelte ~> 0.7.0 which depends on phoenix_live_view ~> 0.18.3, phoenix_live_view ~> 0.18.3 is required.

[Wout De Puysseleir]

Thanks for the bug report! Should now be working starting from version 0.7.1