Update actions/checkout action to v6 (#174)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/codecov-report.yml

@@ -10,7 +10,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
     - name: Set up JDK 11
       uses: actions/setup-java@v5
       with:

.github/workflows/codeql-analysis.yml

@@ -35,7 +35,7 @@ jobs:
 
     steps:
     - name: Checkout repository
-      uses: actions/checkout@v5
+      uses: actions/checkout@v6
 
     # Initializes the CodeQL tools for scanning.
     - name: Initialize CodeQL

.github/workflows/gradle-publish.yml

@@ -7,7 +7,7 @@ jobs:
     runs-on: ubuntu-latest
     environment: ci
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
     - name: Set up JDK 11
       uses: actions/setup-java@v5
       with:

.github/workflows/gradle.yml

@@ -10,7 +10,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
     - name: Set up JDK 11
       uses: actions/setup-java@v5
       with:

.github/workflows/manual-publish.yml

@@ -13,7 +13,7 @@ jobs:
     runs-on: ubuntu-latest
     environment: ci
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
     - name: Set up JDK 11
       uses: actions/setup-java@v5
       with:

.github/workflows/manual-sign.yml

@@ -14,7 +14,7 @@ jobs:
     runs-on: ubuntu-latest
     environment: ci
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
     - name: Set up JDK 11
       uses: actions/setup-java@v5
       with:

.github/workflows/nightly-build.yml

@@ -11,7 +11,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
     - name: Set up JDK 11
       uses: actions/setup-java@v5
       with: