chore: bump circom to 2.1.6

[lonerapier]

closes #92

There are no constraint changes from previous version, but the actual value doesn't match with the one provided in README.

non-linear constraints: 2801097
linear constraints: 0
public inputs: 1
public outputs: 9
private inputs: 2631
private outputs: 0
wires: 2704830
labels: 11813196

[Divide-By-0]

Are there no bumps that need to be made in package.json to the circom or snarkjs packages?

[lonerapier]

circom is installed separately, right.

Should we use the latest version of snarkjs or update the fork to latest upstream?

[Divide-By-0]

We still need to use the forks due to the chunking. If you can update those forks to latest versions of snark js and have tests to ensure they still work with chunking, that would be ideal!

[Divide-By-0]

Done in #185