Bump GitHub checkout action

Author: petk

.github/workflows/check.yaml

@@ -12,7 +12,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
         with:
           fetch-depth: 2
 

.github/workflows/ci.yaml

@@ -109,7 +109,7 @@ jobs:
             sendmail;
 
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
         with:
           fetch-depth: 2
 
@@ -141,7 +141,7 @@ jobs:
     name: Windows
     steps:
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
         with:
           fetch-depth: 2