tests: add license header to integration tests

Author: cakebaker

tests/common/mod.rs

@@ -1,3 +1,6 @@
+// For the full copyright and license information, please view the LICENSE
+// file that was distributed with this source code.
+
 use chrono::{DateTime, FixedOffset};
 use parse_datetime::{parse_datetime, parse_datetime_at_date};
 

tests/date.rs

@@ -1,3 +1,6 @@
+// For the full copyright and license information, please view the LICENSE
+// file that was distributed with this source code.
+
 use rstest::rstest;
 
 mod common;