add more fuzzers

Many thanks to Jemma Nelson
@fwip

fuzz/fuzz_targets/fuzz_parse_time.rs

@@ -0,0 +1,12 @@
+// spell-checker:ignore libfuzzer
+
+#![no_main]
+
+use libfuzzer_sys::fuzz_target;
+use uucore::parse_time;
+
+fuzz_target!(|data: &[u8]| {
+    if let Ok(s) = std::str::from_utf8(data) {
+        _ = parse_time::from_str(s);
+    }
+});