feat(cargo-shuttle): warn about lowercase shuttle.toml (#2060)

Author: jonaro00

cargo-shuttle/src/config.rs

@@ -189,6 +189,9 @@ impl RequestContext {
             .unwrap_or(project_args.working_directory.clone());
 
         trace!("looking for Shuttle.toml in {}", workspace_path.display());
+        if workspace_path.join("shuttle.toml").exists() {
+            eprintln!("WARN: Lowercase 'shuttle.toml' detected, please use 'Shuttle.toml'")
+        }
         let local_manager = LocalConfigManager::new(workspace_path, "Shuttle.toml".to_string());
         let mut project = Config::new(local_manager);
         if !project.exists() {