fix(core): pull package info from tauri.conf.json if set

[lucasfernog]

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[lemarier]

Looks good <3! The main issue I'm seeing is if someone forgot to update the Cargo.toml version (they have to change it at 2 places), the app will announce the tauri.conf.json version but will mismatch the Cargo.toml version who is the real runtime version.

What do you think? Maybe I'm thinking wrong?

[lucasfernog]

The user do not need to update both versions I think (unless they're using the cargo environment variables). The bundler already pulls from the config, and the updater you wrote is using the PackageInfo struct.