add comments and changeset

.changes/updater-add-on-before-request.md

@@ -0,0 +1,5 @@
+---
+"updater": minor
+---
+
+Add `on_before_request` hook to the updater plugin.

plugins/updater/src/updater.rs

@@ -242,6 +242,11 @@ impl UpdaterBuilder {
         self
     }
 
+    /// Allows you to modify the `reqwest`` client builder before the HTTP request is sent.
+    /// 
+    /// Note that `reqwest` crate may be updated in minor releases of tauri-plugin-updater.
+    /// Therefore it's recommended to pin the plugin to at least a minor version when you're using `on_before_request`.
+    ///
     pub fn on_before_request<F: Fn(ClientBuilder) -> ClientBuilder + Send + Sync + 'static>(
         mut self,
         f: F,