v1.1.1

### Releases v1.1.1

1. Add example [**Change_Interval**](examples/Change_Interval)
2. Bump up version to sync with other TimerInterrupt Libraries. Modify Version String.
3. Add new h-only code besides conventional h/cpp code

Author: khoih-prog

CONTRIBUTING.md

@@ -14,7 +14,7 @@ If you don't find anything, please [open a new issue](https://github.com/khoih-p
 
 Please ensure to specify the following:
 
-* Arduino IDE version (e.g. 1.8.11) or Platform.io version
+* Arduino IDE version (e.g. 1.8.13) or Platform.io version
 * `Arduino` Core Version (e.g. Arduino AVR core v1.8.3)
 * Contextual information (e.g. what you were trying to achieve)
 * Simplest possible steps to reproduce