ci: fix json docs generation (#9515)

Author: Andronik Ordian

scripts/gitlab/rpc-docs.sh

@@ -42,9 +42,12 @@ upload_files() {
     git push --tags
 }
 
+RPC_TRAITS_DIR="rpc/src/v1/traits/"
+
 setup_git
 clone_repos
-cp -r parity/ jsonrpc/.parity/
+mkdir -p "jsonrpc/.parity/$RPC_TRAITS_DIR"
+cp -r "$RPC_TRAITS_DIR" "jsonrpc/.parity/$RPC_TRAITS_DIR"
 cd jsonrpc
 build_docs
 cd ..