breaking: drop support for versions less than eslint v8

Author: kazupon

.github/workflows/test.yml

@@ -54,7 +54,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest]
-        eslint: [5, 6, 7, 8, ^9.0.0-0]
+        eslint: [8, ^9.0.0-0]
         node: [20]
     steps:
       - name: Checkout

docs/started.md

@@ -10,7 +10,7 @@ npm install --save-dev eslint @intlify/eslint-plugin-vue-i18n
 
 ::: tip Requirements
 
-- ESLint v5.0.0 or later
+- ESLint v8.0.0 or later
 - Node.js v18.x or later
 
 :::

package.json

@@ -122,7 +122,7 @@
     "vue-github-button": "^3.1.0"
   },
   "peerDependencies": {
-    "eslint": "^5.0.0 || ^6.0.0 || ^7.0.0 || ^8.0.0 || ^9.0.0-0"
+    "eslint": "^8.0.0 || ^9.0.0-0"
   },
   "publishConfig": {
     "access": "public"