Add ws_schema.json to gitignore (#2745)

# Description of Changes

Gitignore a file that's an intermediate artifact of updating the
external client SDKs when the WS protocol gets extended.

# API and ABI breaking changes

N/a

# Expected complexity level and risk

0

# Testing

N/a

Co-authored-by: clockwork-labs-bot <clockwork-labs-bot@users.noreply.github.com>

Author: gefjon

.gitignore

@@ -225,6 +225,9 @@ new.json
 *.pem
 .ok.sql
 
+# Intermediate file generated when updating the external client SDKs' WS format bindings
+crates/client-api-messages/ws_schema.json
+
 # Test data
 !crates/core/testdata/