Increase MSRV to 1.67 (#3234)

* Bump MSRV to 1.67

* clippy fixes

* cargo clippy: inline format args

* Add `clippy::uninlined_format_args` to cranky lints

* Fix clippy on wasm

* More clippy fixes

examples/save_plot/src/main.rs

@@ -14,7 +14,7 @@ fn main() -> Result<(), eframe::Error> {
     eframe::run_native(
         "My egui App with a plot",
         options,
-        Box::new(|_cc| Box::new(MyApp::default())),
+        Box::new(|_cc| Box::<MyApp>::default()),
     )
 }