Add linter to check browser compatibility.

Author: sanason

.browserslistrc

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+# Supported browsers
+last 2 versions
+not dead
+> 0.1%
+Firefox ESR

.gitignore

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+/node_modules

eslint.config.js

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+const compat = require("eslint-plugin-compat");
+
+module.exports = [
+  compat.configs["flat/recommended"]
+];