DID test fixtures and regex escaping fixes

[anweiss]

Addresses #67.

@jonnycrunch FYI I'm adding a bunch of test fixtures based on w3c/did-extensions#138.

[jonnycrunch]

nice! Thanks!

[anweiss]

@jonnycrunch I have added all of your proposed CDDL DID definitions as text fixtures to this crate and all of the known good documents are validating successfully. The known bad documents are also failing to validate as expected. I managed to squash a few parser and validation bugs thanks to your examples. So much appreciated!

Below is my list of findings:

• capabilityDelegation.cddl has a typo on Line 3 ... should be capabilityDelegation and not capabilityDelgation
• example2.json is missing a controller key (you mentioned you would remove this file anyways)
• if service_example1.json is supposed to validate against service.cddl, it will fail because the root type is did-document not serviceEndpoint
• typo in serviceEndpoint.cddl ... should be serviceEndpoint and not serivceEndpoint

[jonnycrunch]

@anweiss Many thanks! I'm working on updating the examples.

[jonnycrunch]

regarding service.cddl , good catch! I owe you a beer! update pending.