fix: disable fs and path for browser usage (webpack 5 compatibility)

[josias-r]

Webpack 5 does not provide nodejs module polyfill by default. This means importing vCards-js in a webpack 5 project does not work anymore. We can define the "browsers" property inside package.json to disable nodejs modules for browser usage.

[josias-r]

@enesser Is this project still maintained?

[vitexikora]

When is it going to be released please?