Bump actions/checkout from 3 to 6

Bumps [actions/checkout](https://github.com/actions/checkout) from 3 to 6.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v3...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/ch07-packaging.yml

@@ -8,7 +8,7 @@ jobs:
     name: Check formatting
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v6
 
       - uses: actions/[email protected]
         with:
@@ -25,7 +25,7 @@ jobs:
     name: Lint
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v6
 
       - uses: actions/[email protected]
         with:
@@ -42,7 +42,7 @@ jobs:
     name: Type check
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v6
 
       - uses: actions/[email protected]
         with:
@@ -66,7 +66,7 @@ jobs:
           - version: "3.9"
             toxenv: "py39"
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v6
 
       - uses: actions/[email protected]
         with:
@@ -83,7 +83,7 @@ jobs:
     name: Build source distribution
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v6
 
       - uses: actions/[email protected]
         with:
@@ -108,7 +108,7 @@ jobs:
         os: [ubuntu-20.04, windows-2019, macOS-10.15]
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v6
 
       - uses: actions/[email protected]
         with:

.github/workflows/ch08-packaging.yml

@@ -8,7 +8,7 @@ jobs:
     name: Check formatting
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v6
 
       - uses: actions/[email protected]
         with:
@@ -25,7 +25,7 @@ jobs:
     name: Lint
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v6
 
       - uses: actions/[email protected]
         with:
@@ -42,7 +42,7 @@ jobs:
     name: Type check
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v6
 
       - uses: actions/[email protected]
         with:
@@ -66,7 +66,7 @@ jobs:
           - version: "3.9"
             toxenv: "py39"
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v6
 
       - uses: actions/[email protected]
         with:
@@ -83,7 +83,7 @@ jobs:
     name: Build source distribution
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v6
 
       - uses: actions/[email protected]
         with:
@@ -108,7 +108,7 @@ jobs:
         os: [ubuntu-20.04, windows-2019, macOS-10.15]
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v6
 
       - uses: actions/[email protected]
         with:

.github/workflows/codeql-analysis.yml

@@ -24,7 +24,7 @@ jobs:
 
     steps:
     - name: Checkout repository
-      uses: actions/checkout@v3
+      uses: actions/checkout@v6
 
     - name: Initialize CodeQL
       uses: github/codeql-action/init@v2