Update checkout action to v6 in template GH actions files

Author: sjvrijn

template/{% if HasWorkflows %}.github{% endif %}/workflows/{% if AddCFFConvert %}cffconvert.yml{% endif %}

@@ -14,7 +14,7 @@ jobs:
     name: "cffconvert"
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         name: Check out a copy of the repository
 
       - name: Check whether the citation metadata from CITATION.cff is valid

template/{% if HasWorkflows %}.github{% endif %}/workflows/{% if AddGitHubActionBuild %}build.yml{% endif %}.jinja

@@ -19,7 +19,7 @@ jobs:
         os: ['ubuntu-latest', 'macos-latest', 'windows-latest']
         python-version: ['3.10', '3.11', '3.12']
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - name: Set up Python ${{ '{{ ' -}} matrix.python-version }}
         uses: actions/setup-python@v6
         with:
@@ -45,7 +45,7 @@ jobs:
     strategy:
       fail-fast: false
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - name: Set up Python 3.12
         uses: actions/setup-python@v6
         with:
@@ -70,7 +70,7 @@ jobs:
     name: Type checking
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - name: Set up Python 3.12
         uses: actions/setup-python@v6
         with:

template/{% if HasWorkflows %}.github{% endif %}/workflows/{% if AddGitHubActionDocumentation %}documentation.yml{% endif %}

@@ -15,7 +15,7 @@ jobs:
     strategy:
       fail-fast: false
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - name: Set up Python 3.12
         uses: actions/setup-python@v6
         with:

template/{% if HasWorkflows %}.github{% endif %}/workflows/{% if AddLinkCheck %}link-check.yml{% endif %}

@@ -19,7 +19,7 @@ jobs:
   linkChecker:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       - name: Link Checker
         id: lychee

template/{% if HasWorkflows %}.github{% endif %}/workflows/{% if AddSonarCloud %}sonarcloud.yml{% endif %}

@@ -15,7 +15,7 @@ jobs:
     name: SonarCloud
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           fetch-depth: 0  # Shallow clones should be disabled for a better relevancy of analysis
       - name: Set up Python

template/{% if HasWorkflows %}.github{% endif %}/workflows/{% if HasWorkflows %}next_steps.yml{% endif %}.jinja

@@ -7,7 +7,7 @@ jobs:
   next_steps:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
 {%- if AddCitation %}
       - name: Create citation data issue