Update dependancy for onoff to avoid issue #170 bug

[wesmc7777]

Purpose

The onoff module is used to blink the LED in the RaspberryPiApp sample.

There was a bug introduced in onoff version < 6.0.0. It was fixed against issue 170 for version 6.0.0 and greater

Updating package.json dependency so anyone learning from the sample does not run into the bug.

Does this introduce a breaking change?

[ ] Yes
[X] No

Pull Request Type

What kind of change does this Pull Request introduce?

[X] Bugfix
[ ] Feature
[ ] Code style update (formatting, local variables)
[ ] Refactoring (no functional changes, no api changes)
[ ] Documentation content changes
[ ] Other... Please describe:

How to Test

• Walk through the documentation tutorial

Without this change you will experience the error mentioned in issue 170.

What to Check

Without this change you will experience the error mentioned in issue 170.

Other Information

N/A