Function update

This function is like set() except that it accepts updater to produce the value to set.

Note: This function mutates object.

Differences from lodash:

• only accepts an array for path, not a dot-separated string
• does not handle customizer returning undefined

Contribution to minified bundle size, when it is the only function imported:

• Lodash: 7,006 bytes
• Micro-dash: 191 bytes