ci: replace xo with directly configured eslint

Author: paulrobertlloyd

.eslintrc.json

@@ -0,0 +1,17 @@
+{
+  "env": {
+    "browser": true,
+    "es2021": true
+  },
+  "extends": [
+    "eslint:recommended",
+    "plugin:jsdoc/recommended",
+    "plugin:unicorn/recommended",
+    "prettier"
+  ],
+  "parserOptions": {
+    "ecmaVersion": "latest",
+    "sourceType": "module"
+  },
+  "plugins": ["jsdoc", "unicorn"]
+}