Upgrade: Bump the actions group across 1 directory with 5 updates (#14731)

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

.github/workflows/release-docs.yml

@@ -15,7 +15,7 @@ jobs:
 
     steps:
     - name: Download source
-      uses: actions/download-artifact@v4
+      uses: actions/download-artifact@v6
       with:
         name: internal-source
 
@@ -78,7 +78,7 @@ jobs:
         echo "::endgroup::"
 
     - name: Store bundles
-      uses: actions/upload-artifact@v4
+      uses: actions/upload-artifact@v5
       with:
         name: openttd-docs
         path: build/bundles/*.tar.xz