Update actions/checkout action to v4 (#159)

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This PR contains the following updates:

| Package | Type | Update | Change |
|---|---|---|---|
| [actions/checkout](https://togithub.com/actions/checkout) | action |
major | `v3` -> `v4` |

---

### Release Notes

<details>
<summary>actions/checkout (actions/checkout)</summary>

###
[`v4`](https://togithub.com/actions/checkout/blob/HEAD/CHANGELOG.md#v400)

[Compare Source](https://togithub.com/actions/checkout/compare/v3...v4)

- [Support fetching without the --progress
option](https://togithub.com/actions/checkout/pull/1067)
-   [Update to node20](https://togithub.com/actions/checkout/pull/1436)

</details>

---

### Configuration

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Automerge - At any time (no schedule defined).

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are satisfied.

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rebase/retry checkbox.

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---

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.github/workflows/links.yml

@@ -13,7 +13,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
 
       - name: Link Checker
         id: lychee

.github/workflows/linting.yml

@@ -11,7 +11,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout source
-        uses: actions/checkout@v3
+        uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
 
       - name: Cache pre-commit
         uses: actions/cache@v3
@@ -36,7 +36,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout source
-        uses: actions/checkout@v3
+        uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
 
       - name: Cache pre-commit
         uses: actions/cache@v3

.github/workflows/pages.yml

@@ -32,7 +32,7 @@ jobs:
       BUNDLE_GEMFILE: ${{ github.workspace }}/docs/Gemfile
     steps:
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
       - name: Setup Ruby
         uses: ruby/setup-ruby@v1
         with:

.github/workflows/test.yml

@@ -13,7 +13,7 @@ jobs:
           - "3.11"
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
 
       - name: Set up Python ${{ matrix.python-version }}
         uses: actions/setup-python@v4