workflows: Add 4.1 entry for Doc PR

Signed-off-by: Hiroshi Hatake <[email protected]>

Author: cosmo0920

.github/workflows/staging-release.yaml

@@ -961,12 +961,20 @@ jobs:
           token: ${{ secrets.GH_PA_TOKEN }}
           ref: 3.2
 
-      - name: Release 4.0 and latest
+      - name: Release 4.0 - not latest
         if: startsWith(inputs.version, '4.0')
         uses: actions/checkout@v5
         with:
           repository: fluent/fluent-bit-docs
           token: ${{ secrets.GH_PA_TOKEN }}
+          ref: 4.0
+
+      - name: Release 4.1 and latest
+        if: startsWith(inputs.version, '4.1')
+        uses: actions/checkout@v5
+        with:
+          repository: fluent/fluent-bit-docs
+          token: ${{ secrets.GH_PA_TOKEN }}
 
       - name: Ensure we have the script we need
         run: |