fix: eslint settings (#787)

Co-authored-by: Dominik Pschenitschni <mail@celement.de>
Reviewed-on: vikunja/frontend#787
Co-authored-by: dpschen <dpschen@noreply.kolaente.de>
Co-committed-by: dpschen <dpschen@noreply.kolaente.de>

package.json

@@ -78,11 +78,13 @@
   "eslintConfig": {
     "root": true,
     "env": {
+      "browser": true,
+      "es2021": true,
       "node": true
     },
     "extends": [
-      "plugin:vue/essential",
       "eslint:recommended",
+      "plugin:vue/essential",
       "@vue/typescript"
     ],
     "rules": {
@@ -103,8 +105,10 @@
         "never"
       ]
     },
+    "parser": "vue-eslint-parser",
     "parserOptions": {
-      "parser": "@typescript-eslint/parser"
+      "parser": "@typescript-eslint/parser",
+      "ecmaVersion": 2021
     },
     "ignorePatterns": [
       "*.test.*",