chore(docs): bump actions/checkout to v6

Signed-off-by: Rui Chen <rui@chenrui.dev>

Author: chenrui333

README.md

@@ -36,7 +36,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 +     - name: Turnstyle
 +       uses: softprops/turnstyle@v3
       - name: Deploy
@@ -60,7 +60,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       - name: Turnstyle
         uses: softprops/turnstyle@v3
       - name: Deploy
@@ -79,7 +79,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       - name: Turnstyle
         uses: softprops/turnstyle@v3
         with:
@@ -100,7 +100,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       - name: Turnstyle
         uses: softprops/turnstyle@v3
         with:
@@ -122,7 +122,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       - name: Turnstyle
         uses: softprops/turnstyle@v3
         with:
@@ -147,7 +147,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       - name: Turnstyle
         id: turnstyle
         uses: softprops/turnstyle@v3