chore(deps): update actions/checkout action to v6 (#2102)

This PR contains the following updates:

| Package | Type | Update | Change |
|---|---|---|---|
| [actions/checkout](https://redirect.github.com/actions/checkout) |
action | major | `v5` -> `v6` |

---

### Release Notes

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

### [`v6`](https://redirect.github.com/actions/checkout/compare/v5...v6)

[Compare
Source](https://redirect.github.com/actions/checkout/compare/v5...v6)

</details>

---

### Configuration

📅 **Schedule**: Branch creation - "every weekday" (UTC), 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/apify/apify-docs).

<!--renovate-debug:eyJjcmVhdGVkSW5WZXIiOiI0Mi4xNi4xIiwidXBkYXRlZEluVmVyIjoiNDIuMTYuMSIsInRhcmdldEJyYW5jaCI6Im1hc3RlciIsImxhYmVscyI6W119-->

<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> Bump actions/checkout from v5 to v6 across all GitHub Actions
workflows (docs, lychee, openapi, publish-to-npm, test, vale).
> 
> <sup>Written by [Cursor
Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit
c129b8c. Configure
[here](https://cursor.com/dashboard?tab=bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

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

Author: renovate[bot]

.github/workflows/docs.yaml

@@ -17,7 +17,7 @@ jobs:
         runs-on: ubuntu-latest
 
         steps:
-            -   uses: actions/checkout@v5
+            -   uses: actions/checkout@v6
             -   name: Use Node.js 22
                 uses: actions/setup-node@v6
                 with:

.github/workflows/lychee.yml

@@ -9,7 +9,7 @@ jobs:
     link-check:
         runs-on: ubuntu-latest
         steps:
-            -   uses: actions/checkout@v5
+            -   uses: actions/checkout@v6
 
             -   name: Use Node.js 22
                 uses: actions/setup-node@v6

.github/workflows/openapi.yaml

@@ -9,7 +9,7 @@ jobs:
         runs-on: ubuntu-latest
 
         steps:
-            - uses: actions/checkout@v5
+            - uses: actions/checkout@v6
 
             - name: Use Node.js 24
               uses: actions/setup-node@v6
@@ -35,7 +35,7 @@ jobs:
         runs-on: ubuntu-latest
 
         steps:
-            - uses: actions/checkout@v5
+            - uses: actions/checkout@v6
 
             - name: Use Node.js 24
               uses: actions/setup-node@v6

.github/workflows/publish-to-npm.yaml

@@ -17,7 +17,7 @@ jobs:
         outputs:
             theme_changed: ${{ steps.changed-theme-files.outputs.any_changed }}
         steps:
-            -   uses: actions/checkout@v5
+            -   uses: actions/checkout@v6
                 with:
                     fetch-depth: 0
 
@@ -45,7 +45,7 @@ jobs:
         if: ${{ needs.look_for_change.outputs.theme_changed == 'true' || github.event_name == 'workflow_dispatch' }}
         runs-on: ubuntu-latest
         steps:
-            -   uses: actions/checkout@v5
+            -   uses: actions/checkout@v6
                 with:
                     token: ${{ secrets.APIFY_SERVICE_ACCOUNT_GITHUB_TOKEN }}
 

.github/workflows/test.yaml

@@ -11,7 +11,7 @@ jobs:
         runs-on: ubuntu-latest
         steps:
             -   name: Checkout Source code
-                uses: actions/checkout@v5
+                uses: actions/checkout@v6
 
             -   name: Use Node.js 22
                 uses: actions/setup-node@v6
@@ -144,7 +144,7 @@ jobs:
         runs-on: ubuntu-latest
         steps:
             -   name: Checkout Source code
-                uses: actions/checkout@v5
+                uses: actions/checkout@v6
 
             -   name: Get changed files
                 id: changed-files
@@ -185,7 +185,7 @@ jobs:
         runs-on: ubuntu-latest
         steps:
             -   name: Checkout Source code
-                uses: actions/checkout@v5
+                uses: actions/checkout@v6
 
             -   name: Use Node.js 22
                 uses: actions/setup-node@v6

.github/workflows/vale.yaml

@@ -7,7 +7,7 @@ jobs:
         runs-on: ubuntu-latest
 
         steps:
-            -   uses: actions/checkout@v5
+            -   uses: actions/checkout@v6
                 with:
                     fetch-depth: 0