Upgrade toe checkout@v3, to prevent warning 'Node.js 12 actions are deprecated.'

Author: spier

.github/workflows/i18n-consistency-checker.yaml

@@ -17,7 +17,7 @@ jobs:
       matrix:
         language: [ja, zh]
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
         with:
           fetch-depth: '0'
       - name: Check consistency