Function Goldbach

Goldbach(num: number): [number, number] | undefined
Returns an even number as a sum of two prime numbers.
Parameters
- num: number
  Even number
Returns [number, number] | undefined
Example
```
// Returns [5, 7]
const primes = Chalkboard.numb.Goldbach(12);
```
- Defined in Chalkboard.numb.ts:498