Remove ./node_modules/ from require in example

[ajlende]

Description

Noticed this when following the example for configuring webpack. Node will automatically resolve modules from the node_modules directory, so ./node_modules/ doesn't need to be listed in the require.

Types of changes

Documentation

Checklist:

• My code is tested.
• My code follows the WordPress code style.
• My code follows the accessibility standards.
• My code has proper inline documentation.
• I've included developer documentation if appropriate.

[aduth]

Thanks for the improvement!