Adding whenever in date & time section (#9)

* Add 'whenever' library to Date & Time section

* Fix punctuation in 'whenever' description

Author: KishanPipariya

README.md

@@ -72,6 +72,7 @@ This list tracks the growing movement of Python projects leveraging Rust for the
 ## Date & Time
 
 - [pendulum](https://github.com/python-pendulum/pendulum) - Python datetimes made easy; performance-critical parts rewritten from C to Rust in v3.
+- [whenever](https://github.com/ariebovenberg/whenever) - Typed and DST-safe datetimes for Python.
 
 ## Data Structures