community/dino: add libomemo-c-dev to makedepends

libomemo-c-dev is needed at compile time for omemo. Otherwise, dino keeps sending

I sent you an OMEMO encrypted message but your client doesn’t seem to support that. Find more information on https://conversations.im/omemo

or

[This message is OMEMO encrypted]

for omemo messages. I tested this locally and this package works.