Use namehash from ethers.utils

no need for the additional dependency

package-lock.json

@@ -2888,6 +2888,7 @@
       "version": "2.0.8",
       "resolved": "https://registry.npmjs.org/eth-ens-namehash/-/eth-ens-namehash-2.0.8.tgz",
       "integrity": "sha1-IprEbsqG1S4MmR58sq74P/D2i88=",
+      "dev": true,
       "requires": {
         "idna-uts46-hx": "^2.3.1",
         "js-sha3": "^0.5.7"
@@ -10174,6 +10175,7 @@
       "version": "2.3.1",
       "resolved": "https://registry.npmjs.org/idna-uts46-hx/-/idna-uts46-hx-2.3.1.tgz",
       "integrity": "sha512-PWoF9Keq6laYdIRwwCdhTPl60xRqAloYNMQLiyUnG42VjT53oW07BXIRM+NK7eQjzXjAk2gUvX9caRxlnF9TAA==",
+      "dev": true,
       "requires": {
         "punycode": "2.1.0"
       }
@@ -13078,7 +13080,8 @@
     "punycode": {
       "version": "2.1.0",
       "resolved": "https://registry.npmjs.org/punycode/-/punycode-2.1.0.tgz",
-      "integrity": "sha1-X4Y+3Im5bbCQdLrXlHvwkFbKTn0="
+      "integrity": "sha1-X4Y+3Im5bbCQdLrXlHvwkFbKTn0=",
+      "dev": true
     },
     "qs": {
       "version": "6.7.0",