[Bug] : In mobile screen need to center the footer

[harshal050]

In mobile screen need to center the footer

issue fix:#328

Steps :

1 : Open site in mobile screen
2 : Go to https://nightwatchjs.org/
3 : Go to footer
4 : Fix the Nightwatch.js and Help component to center

[shreyashap]

• Fix mobile screen footer center #344