chore(deps): update actions/checkout action to v5 (#33)

This PR contains the following updates:

| Package | Type | Update | Change |
|---|---|---|---|
| [actions/checkout](https://redirect.github.com/actions/checkout) |
action | major | `v4` -> `v5` |

---

### Release Notes

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

### [`v5`](https://redirect.github.com/actions/checkout/compare/v4...v5)

[Compare
Source](https://redirect.github.com/actions/checkout/compare/v4...v5)

</details>

---

### Configuration

📅 **Schedule**: Branch creation - At any time (no schedule defined),
Automerge - At any time (no schedule defined).

🚦 **Automerge**: Disabled by config. Please merge this manually once you
are satisfied.

♻ **Rebasing**: Whenever PR becomes conflicted, or you tick the
rebase/retry checkbox.

🔕 **Ignore**: Close this PR and you won't be reminded about this update
again.

---

- [ ] <!-- rebase-check -->If you want to rebase/retry this PR, check
this box

---

This PR was generated by [Mend Renovate](https://mend.io/renovate/).
View the [repository job
log](https://developer.mend.io/github/tweag/run-nix-shell).

<!--renovate-debug:eyJjcmVhdGVkSW5WZXIiOiI0MS42MC40IiwidXBkYXRlZEluVmVyIjoiNDEuMTMxLjkiLCJ0YXJnZXRCcmFuY2giOiJtYWluIiwibGFiZWxzIjpbXX0=-->

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/ci.yaml

@@ -22,7 +22,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     steps:
       - name: Checkout the repository
-        uses: actions/checkout@08eba0b27e820071cde6df949e0beb9ba4906955 # v4
+        uses: actions/checkout@93cb6efe18208431cddfb8368fd83d5badbf9bfd # v5
       - uses: ./.github/actions/set_up_runner
         with:
           github_token: ${{ secrets.GITHUB_TOKEN }}
@@ -39,7 +39,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     steps:
       - name: Checkout the repository
-        uses: actions/checkout@08eba0b27e820071cde6df949e0beb9ba4906955 # v4
+        uses: actions/checkout@93cb6efe18208431cddfb8368fd83d5badbf9bfd # v5
       - uses: ./.github/actions/set_up_runner
         with:
           github_token: ${{ secrets.GITHUB_TOKEN }}

.github/workflows/move_major_ver_tag_on_release.yml

@@ -18,7 +18,7 @@ jobs:
       # branches and tags. This is important if the workflow is launched via
       # workspace_dispatch event. It ensures that we can find the release tag
       # and the major version tag.
-      - uses: actions/checkout@08eba0b27e820071cde6df949e0beb9ba4906955 # v4
+      - uses: actions/checkout@93cb6efe18208431cddfb8368fd83d5badbf9bfd # v5
         with:
           # Fetch all history for all branches and tags
           fetch-depth: 0