use older symlink check function (#3579)

Co-authored-by: Lucas Nogueira <lucas@tauri.studio>

.changes/rust-1.57-usage.md

@@ -0,0 +1,5 @@
+---
+"tauri-utils": patch
+---
+
+Use `is_symlink` API compatible with Rust v1.57 instead of std/fs/struct.Metadata.html#method.is_symlink.

core/tauri-utils/src/platform/starting_binary.rs

@@ -68,7 +68,9 @@ impl StartingBinary {
         ancestor
           .symlink_metadata()
           .as_ref()
-          .map(std::fs::Metadata::is_symlink),
+          .map(std::fs::Metadata::file_type)
+          .as_ref()
+          .map(std::fs::FileType::is_symlink),
         Ok(true)
       )
     })