chore(opener): Fix Cargo.toml property name for tauri-docs generator

plugins/opener/Cargo.toml

@@ -15,7 +15,7 @@ rustdoc-args = ["--cfg", "docsrs"]
 # Platforms supported by the plugin
 # Support levels are "full", "partial", "none", "unknown"
 # Details of the support level are left to plugin maintainer
-[package.metadata.platforms]
+[package.metadata.platforms.support]
 windows = { level = "full", notes = "" }
 linux = { level = "full", notes = "" }
 macos = { level = "full", notes = "" }