1. use `ProviderError` to catch contract errors instaed of `JsonRpcProviderError`.
2. Add tests for `isProofRequired`, `willProofBeRequired`, and `getProofEnd` when slot is empty (and is call is reverted)
3. bump nim-ethers to branch that has new `reverts` API and `ProviderError` support.
4. Update to new `reverts` API.