Bump actions/checkout from 5 to 6

Bumps [actions/checkout](https://github.com/actions/checkout) from 5 to 6.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v5...v6)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

.github/workflows/check-go-task.yml

@@ -67,7 +67,7 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Install Go
         uses: actions/setup-go@v6
@@ -100,7 +100,7 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Install Go
         uses: actions/setup-go@v6
@@ -136,7 +136,7 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Install Go
         uses: actions/setup-go@v6
@@ -172,7 +172,7 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Install Go
         uses: actions/setup-go@v6
@@ -208,7 +208,7 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Install Go
         uses: actions/setup-go@v6

.github/workflows/check-markdown-task.yml

@@ -69,7 +69,7 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Setup Node.js
         uses: actions/setup-node@v6
@@ -95,7 +95,7 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Setup Node.js
         uses: actions/setup-node@v6

.github/workflows/check-prettier-formatting-task.yml

@@ -211,7 +211,7 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Setup Node.js
         uses: actions/setup-node@v6

.github/workflows/check-taskfiles.yml

@@ -39,7 +39,7 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Setup Node.js
         uses: actions/setup-node@v6

.github/workflows/release.yml

@@ -43,18 +43,18 @@ jobs:
 
     steps:
       - name: Checkout rp2040tools repository
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
         with:
           path: rp2040tools
 
       - name: Checkout picotool
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
         with:
           repository: raspberrypi/picotool
           path: picotool
 
       - name: Checkout pico-sdk
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
         with:
           repository: raspberrypi/pico-sdk
           path: pico-sdk
@@ -153,7 +153,7 @@ jobs:
 
     steps:
       - name: Checkout rp2040tools repository
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Install Go
         uses: actions/setup-go@v6
@@ -194,7 +194,7 @@ jobs:
       PROJECT_NAME: rp2040tools
     steps:
       - name: Checkout rp2040tools repository # we need package_index.template
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Download artifact
         uses: actions/download-artifact@v6 # download all the artifacts

.github/workflows/sync-labels.yml

@@ -27,7 +27,7 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Download JSON schema for labels configuration file
         id: download-schema
@@ -106,7 +106,7 @@ jobs:
           echo "::set-output name=flag::--dry-run"
 
       - name: Checkout repository
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Download configuration file artifacts
         uses: actions/download-artifact@v6