Use log crate instead of eprintln & remove some unwraps (#5010)

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- I fixed the TODO to use the `log` crate instead of `eprintln`
- Set the rust-version in the `scripts/check.sh` to the same as egui is
on
- I made xtask use anyhow to remove some unwraps 

* [x] I have followed the instructions in the PR template

crates/eframe/src/native/glow_integration.rs

@@ -1547,7 +1547,7 @@ fn save_screenshot_and_exit(
     .unwrap_or_else(|err| {
         panic!("Failed to save screenshot to {path:?}: {err}");
     });
-    eprintln!("Screenshot saved to {path:?}.");
+    log::info!("Screenshot saved to {path:?}.");
 
     #[allow(clippy::exit)]
     std::process::exit(0);