build(deps): bump actions/checkout from 3 to 6

.github/workflows/dev.yaml

@@ -20,7 +20,7 @@ jobs:
 
     steps:
       - name: checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v6
 
       - name: setup python
         uses: actions/setup-python@v5

.github/workflows/docs.yaml

@@ -12,7 +12,7 @@ jobs:
     runs-on: ubuntu-24.04
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v6
         with:
           # Fetch the history for all tags and branches
           # so that the correct version string can be constructed
@@ -43,7 +43,7 @@ jobs:
 
       - name: Checkout docs site
         if: (!github.event.pull_request)
-        uses: actions/checkout@v3
+        uses: actions/checkout@v6
         with:
           repository: popsim-consortium/demes-docs
           token: ${{ secrets.POPSIMBOT_DEMES_DOCS_TOKEN }}

.github/workflows/lint.yaml

@@ -10,7 +10,7 @@ jobs:
   lint:
     runs-on: ubuntu-24.04
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v6
       - uses: actions/setup-python@v5
         with:
           python-version: "3.12"

.github/workflows/tests.yaml

@@ -32,7 +32,7 @@ jobs:
 
     steps:
       - name: checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v6
         with:
           submodules: true
 

.github/workflows/wheel.yaml

@@ -13,7 +13,7 @@ jobs:
   wheel_build:
     runs-on: ubuntu-24.04
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v6
       - uses: actions/setup-python@v5
         with:
           python-version: "3.12"