fix: node 16 module resolution error

[bsssshhhhhhh]

Description

Adds a "types" field to the exports block in package.json to allow TypeScript's Node16 resolution to work properly.

Without it, TypeScript throws this error:

Could not find a declaration file for module 'vuestic-ui'. '/workspace/node_modules/vuestic-ui/dist/es/main.js' implicitly has an 'any' type.
  There are types at '/workspace/node_modules/vuestic-ui/dist/types/main.d.ts', but this result could not be resolved when respecting package.json "exports". The 'vuestic-ui' library may need to update its package.json or typings

Markup:

// Your code

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Improvement/refactoring (non-breaking change that doesn't add any feature but make things better)

[m0ksem]

Thanks!