Slight typo: `vnd.org.cncf....`

[imjasonh]

In filtering examples, you reference the artifact type application/vnd.org.cncf.notary.v2. I think you mean to use application/vnd.cncf.notary.v2 (no org.), since this makes it seem like it's a reverse-domain-name scheme referring to cncf.org which is unaffiliated with the CNCF (https://cncf.io).

This is moot if filtering is pinned for later (#68), or if specific example media types are removed (#66), but in case those don't come to pass, we should fix the typo.

[SteveLasker]

@imjasonh, thanks for the catch. We've had a number of changes to names. Please feel free to make the PR, or I can do some cleanup as part of #66

[SteveLasker]

Closing as a result of #71