Add a timeout to symbol downloads

The number I picked here is kinda arbitrary.

Fixes rust-minidump#300

breakpad-symbols/src/lib.rs

@@ -349,7 +349,10 @@ impl HttpSymbolSupplier {
         tmp: PathBuf,
         mut local_paths: Vec<PathBuf>,
     ) -> HttpSymbolSupplier {
-        let client = Client::new();
+        let client = Client::builder()
+            .timeout(std::time::Duration::from_secs(30))
+            .build()
+            .unwrap();
         let urls = urls
             .into_iter()
             .filter_map(|mut u| {