ci: fix publisher binary copy path

Author: masnwilliams

.github/workflows/publish-mcp.yml

@@ -32,7 +32,7 @@ jobs:
           git clone https://github.com/modelcontextprotocol/registry publisher-repo
           cd publisher-repo
           make publisher
-          cp cmd/publisher/bin/mcp-publisher ../mcp-publisher
+          cp bin/mcp-publisher ../mcp-publisher
           cd ..
           chmod +x mcp-publisher