Update build-agent-splunk pipeline release step (#1039)

Author: git-hyagi

.github/workflows/build-agent-splunk.yml

@@ -53,6 +53,5 @@ jobs:
           else
             gh release create "$TAG" \
               --title "agent-splunk $TAG" \
-              --generate-notes \
               agent-splunk
           fi

tools/agents/agent-splunk/README.md

@@ -41,3 +41,4 @@ go build -o agent-splunk .
 podman build -f Containerfile -t agent-splunk .
 podman run --env-file .env agent-splunk
 ```
+