Feature wheel sensitivity

[Farkites]

About

Adds feature to set wheelSensitivity, using code from #150 by @kinimesi

Description of changes

• Implements wheelSensitivity that controls the zoom speed when using the scroll wheel on the Dash Cytoscape component.

Pre-Merge checklist

• The project was correctly built with npm run build:all.
• If there was any conflict, it was solved correctly.
• All changes were documented in CHANGELOG.md.
• All tests on CircleCI have passed.
• All Percy visual changes have been approved.
• Two people have 💃'd the pull request. You can be one of these people if you are a Dash Cytoscape core contributor.

Closes #97

[emilykl]

Working for me! 🎉

I also tested wheelSensitivity in the CyLeaflet demo for a sanity check and it works as expected. 🦾

[alexcjohnson]

💃