Update dependency ethers to v6

Author: renovate[bot]

package.json

@@ -38,7 +38,7 @@
 		"eslint-config-xo": "0.43.1",
 		"eslint-config-xo-typescript": "0.57.0",
 		"ethereum-waffle": "3.4.4",
-		"ethers": "5.8.0",
+		"ethers": "6.15.0",
 		"hardhat": "2.9.9",
 		"husky": "7.0.4",
 		"mocha": "9.2.2",