Merge pull request #4526 from tertsdiepraam/date-d-should-return-1

`date`: make sure 'invalid date' message also returns exit code 1

tests/by-util/test_date.rs

@@ -300,3 +300,13 @@ fn test_invalid_format_string() {
     result.no_stdout();
     assert!(result.stderr_str().starts_with("date: invalid format "));
 }
+
+#[test]
+fn test_invalid_date_string() {
+    new_ucmd!()
+        .arg("-d")
+        .arg("foo")
+        .fails()
+        .no_stdout()
+        .stderr_contains("invalid date");
+}