Missing "4.8 Amend Claim" section

[laysakura]

Slightly related to: #133

While the Figure 3 contains "8. Amend Claim", "4.8 Amend Claim" section is missing.

[jandrieu]

Closing as a duplicate of #124 which is still under discussion as #133.

One of us editors leans towards getting rid of it, but the other thinks there are important notions we should discuss about replacing a VC when it is no longer valid. Not so much as amend claim, perhaps, as update the credential with an updated claim. There are philosophical issues about whether or not this is "amending" the initial claim or a second, different claim, but the state transition from one claim to another related claim is something we want to discuss.