Update build.yml

Author: HSGamer

.github/workflows/build.yml

@@ -16,7 +16,7 @@ jobs:
         uses: actions/checkout@v4
         with:
           repository: PaperMC/Folia
-          ref: ver/1.21.5
+          ref: ver/1.21.6
           path: Folia
       - name: Checkout the Publish Repo
         uses: actions/checkout@v4