Update for recent api changes
Use fix "tree-head:v0@sigsum.org" namespace for tree head signatures, and include log's key hash elsewhere in the signed data.
Put key hash and cosignature on the same line when posting an add-cosignature request.
Use fix "tree-head:v0@sigsum.org" namespace for tree head signatures, and include log's key hash elsewhere in the signed data.
Put key hash and cosignature on the same line when posting an add-cosignature request.