chore(deps): update actions/checkout action to v6

Author: renovate[bot]

.github/workflows/main.yml

@@ -6,7 +6,7 @@ jobs:
 
     steps:
       - name: Begin CI...
-        uses: actions/checkout@v2
+        uses: actions/checkout@v6
 
       - name: Use Node 12
         uses: actions/setup-node@v2

.github/workflows/release.yml

@@ -9,7 +9,7 @@ jobs:
   release_package:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v6
 
       - name: "yarn install"
         run: yarn install --frozen-lockfile