Update actions/checkout action to v6

Author: renovate[bot]

.github/workflows/android.yml

@@ -8,7 +8,7 @@ jobs:
     runs-on: macos-latest
 
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
     - name: set up JDK 21
       uses: actions/setup-java@v5
       with:

.github/workflows/build-and-publish-web.yml

@@ -19,7 +19,7 @@ jobs:
 
       # Check out current repository
       - name: Fetch Sources
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       # Build application
       - name: Build

.github/workflows/ios.yml

@@ -12,7 +12,7 @@ jobs:
   build:
     runs-on: macos-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: actions/setup-java@v5
         with:
           distribution: 'zulu'