Use the MSRV-aware resolver instead of pinning versions in CI

Resolver 3 skips dependency versions whose rust-version is above
ours, so the CI lockfile step no longer needs --precise pins that
must be maintained by hand.
This is also more reliable as more crate are release with higher MSRV

Cargo.toml

@@ -1,7 +1,7 @@
 [workspace]
 default-members = ["winit"]
 members = ["dpi", "winit*"]
-resolver = "2"
+resolver = "3"
 
 [workspace.package]
 edition = "2024"