Exercise on the Pedersen hash

[tekkac]

Description

The native hash function in Cairo is the pedersen hash builtin.
Show how to use the hash2 function on multiple inputs.

Resource:

• https://www.cairo-lang.org/docs/how_cairo_works/builtins.html#introduction
• https://perama-v.github.io/cairo/cairo-common-library/#hash

Acceptance criteria

• The exercise show how to hash a message
• The contract compiles and tests pass
• An exercise patch is generated