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/epaint/src/tessellator.rs

@@ -1749,8 +1749,12 @@ impl Tessellator {
         }
 
         if galley.pixels_per_point != self.pixels_per_point {
-            eprintln!("epaint: WARNING: pixels_per_point (dpi scale) have changed between text layout and tessellation. \
-                       You must recreate your text shapes if pixels_per_point changes.");
+            let warn = "epaint: WARNING: pixels_per_point (dpi scale) have changed between text layout and tessellation. \
+                       You must recreate your text shapes if pixels_per_point changes.";
+            #[cfg(feature = "log")]
+            log::warn!("{warn}");
+            #[cfg(not(feature = "log"))]
+            println!("{warn}");
         }
 
         out.vertices.reserve(galley.num_vertices);