Allow dispatch of release drafter (#12)

Signed-off-by: Jacob Tomlinson <jtomlinson@nvidia.com>

.github/workflows/release-drafter.yaml

@@ -4,6 +4,7 @@ on:
   push:
     branches:
       - main
+  workflow_dispatch:
   # pull_request event is required only for autolabeler
   pull_request:
     # Only following types are handled by the action, but one can default to all as well