ci: bump conventional-pr workflow to v1.2.1

Human-readable type labels with enforced descriptions and colors.

TRI-1100

Author: mc-nv

.github/workflows/conventional-pr.yml

@@ -38,4 +38,4 @@ jobs:
   conventional-pr:
     permissions:
       pull-requests: write
-    uses: triton-inference-server/.github/.github/workflows/conventional-pr.yml@v1.1.0
+    uses: triton-inference-server/.github/.github/workflows/conventional-pr.yml@v1.2.1