Update to newer feature/stream-mode branch in fxamacker/cbor

[fxamacker]

Currently, fxamacker/cbor's feature/stream-mode branch is still based on v2.4.

After updating fxamacker'cbor's feature/stream-mode branch to be based on v2.7, I will update atree to use it.

This requires fuzz testing fxamacker/cbor's feature branch, smoke testing atree, and making sure this change doesn't break onflow/cadence, onflow/flow-go, etc.

NOTE: Eventually, I will add stream mode to the main branch of fxamacker/cbor along with some improvements.

[fxamacker]

As mentioned in PR #542, we should make sure various tests pass before merging any PRs to main branch:

• longer duration smoke testing
• backward compatibility tests using testnet blocks
• backward compatibility tests using mainnet blocks
• integration tests in other projects.