Update pseudo random generation to use math/rand/v2

[fedevilensky]

Pseudorandom number generation should be updated to use math/rand/v2 as this is the new recommended implementation

[ottosulin]

No, crypto/rand should still be used for security-sensitive operations.

"For example, using math/rand to generate a 128-bit or 256-bit AES key would be a serious mistake, since the key would be easier to brute force. For that kind of use, you need a cryptographically strong random number generator, as provided by crypto/rand" - golang blog.

"This package's outputs might be easily predictable regardless of how it's seeded. For random numbers suitable for security-sensitive work, see the crypto/rand package" - math/rand/v2 docs

[fedevilensky]

Sorry maybe I was not clear enough. I meant instead of "math/rand" use "math/rand/v2"