Update dependency ethers to v5.6.8

[renovate[bot]]

This PR contains the following updates:

Package	Change	Age	Adoption	Passing	Confidence
ethers	5.6.7 -> 5.6.8

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Release Notes

ethers-io/ethers.js

### [`v5.6.8`](https://togithub.com/ethers-io/ethers.js/blob/HEAD/CHANGELOG.md#ethersv568-2022-05-24-1150) [Compare Source](https://togithub.com/ethers-io/ethers.js/compare/v5.6.7...v5.6.8) - Update BN.js for hexstring bug fix. ([#​3017](https://togithub.com/ethers-io/ethers.js/issues/3017); [30b716b](https://togithub.com/ethers-io/ethers.js/commit/30b716bf2cfd67ca38f76e344a26c0c2d5b75935), [a27ef82](https://togithub.com/ethers-io/ethers.js/commit/a27ef825772f72071439c51e51180b6fcc64f03c))

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Configuration

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