build: add eslint as dev dep

package.json

@@ -80,6 +80,7 @@
     "@blockstack/prettier-config": "^0.0.6",
     "@next/bundle-analyzer": "^9.4.4",
     "babel-plugin-styled-components": "^1.11.0",
+    "eslint": "^7.6.0",
     "husky": "^4.2.5",
     "next-transpile-modules": "^4.0.2",
     "react": "^16.13.0",

yarn.lock

@@ -4279,7 +4279,7 @@ eslint-visitor-keys@^1.1.0, eslint-visitor-keys@^1.3.0:
   resolved "https://registry.yarnpkg.com/eslint-visitor-keys/-/eslint-visitor-keys-1.3.0.tgz#30ebd1ef7c2fdff01c3a4f151044af25fab0523e"
   integrity sha512-6J72N8UNa462wa/KFODt/PJ3IU60SDpC3QXC1Hjc1BXXpfL2C9R5+AU7jhe0F6GREqVMh4Juu+NY7xn+6dipUQ==
 
-eslint@^7.1.0, eslint@^7.4.0:
+eslint@^7.1.0, eslint@^7.4.0, eslint@^7.6.0:
   version "7.6.0"
   resolved "https://registry.yarnpkg.com/eslint/-/eslint-7.6.0.tgz#522d67cfaea09724d96949c70e7a0550614d64d6"
   integrity sha512-QlAManNtqr7sozWm5TF4wIH9gmUm2hE3vNRUvyoYAa4y1l5/jxD/PQStEjBMQtCqZmSep8UxrcecI60hOpe61w==