[Idea] Add fuzz testing

[andresuribe87]

Is your feature request related to a problem? Please describe.
The SDK can be hardenned further by incorporating fuzz tests in many of the functions.

Describe the solution you'd like
Fuzz tests added in the did package. A good candidate is the key DID method. A fuzz test could test the property that "Generate and then resolve returns a document with the same ID".

Describe alternatives you've considered
N/A

Getting it done
Looking for contibutors :)

Path to SIP
No, this is a simple test to be added for hardening.

Additional context
See this doc for more details on how to do fuzz testing: https://go.dev/security/fuzz/