Updated checkout action version.

Author: akb825

.github/workflows/main.yml

@@ -41,7 +41,7 @@ jobs:
           artifact: 1
     steps:
     - name: checkout
-      uses: actions/checkout@v4
+      uses: actions/checkout@v6
     - name: Download submodules
       run: |-
         git submodule update --init
@@ -143,7 +143,7 @@ jobs:
           artifact: 1
     steps:
     - name: checkout
-      uses: actions/checkout@v4
+      uses: actions/checkout@v6
     - name: Download submodules
       run: |-
         git submodule update --init
@@ -267,7 +267,7 @@ jobs:
           artifact: win64-full
     steps:
     - name: checkout
-      uses: actions/checkout@v4
+      uses: actions/checkout@v6
     - name: Download submodules
       run: |-
         git submodule update --init