Add eslint to the project

This will allow us to catch bugs earlier while developing the extension.

Change-Id: Iaa9b8870c0fabc603517bb5ec1b3ae4a81191ca0
diff --git a/.eslintrc.json b/.eslintrc.json
new file mode 100644
index 0000000..b110eaa
--- /dev/null
+++ b/.eslintrc.json
@@ -0,0 +1,19 @@
+{
+    "env": {
+        "browser": true,
+        "webextensions": true,
+        "es2021": true
+    },
+    "extends": "eslint:recommended",
+    "overrides": [
+    ],
+    "parserOptions": {
+        "ecmaVersion": "latest",
+        "sourceType": "module"
+    },
+    "rules": {
+    },
+    "ignorePatterns": [
+      "webpack.config.js"
+    ]
+}