Resolve clippy::unnecessary_map_or warning (#2904)

Author: brody4hire

futures/tests/no-std/build.rs

@@ -11,5 +11,5 @@ fn is_nightly() -> bool {
     env::var_os("RUSTC")
         .and_then(|rustc| Command::new(rustc).arg("--version").output().ok())
         .and_then(|output| String::from_utf8(output.stdout).ok())
-        .map_or(false, |version| version.contains("nightly") || version.contains("dev"))
+        .is_some_and(|version| version.contains("nightly") || version.contains("dev"))
 }