Update dependencies to keep-ecdsa and tbtc-v2 packages (#636)

We have published new `@keep-network/ecdsa` and `@keep-network/tbtc-v2`
packages. Those packages no longer include the `prepare-dependencies.sh`
script from `@threshold-network/solidity-contracts` which was causing
random failures during `yarn install`. As in some CI jobs we install the
dependencies based on the lockfile (with the `--frozen-lockfile` flag),
we need to update dependencies in the lockfile so that the new, improved
packages would be used.

Ref:
threshold-network/solidity-contracts#142
threshold-network/solidity-contracts#143
#631