docs: add the ESLint plugin announcement (#1759)

Author: andrii-bodnar

website/docusaurus.config.js

@@ -15,6 +15,14 @@ module.exports = {
       disableSwitch: false,
       respectPrefersColorScheme: true,
     },
+    announcementBar: {
+      id: "eslint-plugin",
+      content:
+        '🎉 The Lingui ESLint plugin is now available, <a target="_blank" rel="noopener noreferrer" href="https://lingui.dev/ref/eslint-plugin">check it out!</a>',
+      backgroundColor: "#ef4242",
+      textColor: "#FFFFFF",
+      isCloseable: true,
+    },
     navbar: {
       title: "",
       logo: {