Update core agent to 1.5.1

Author: jrothrock

src/scout_apm/core/config.py

@@ -229,7 +229,7 @@ def __init__(self):
             "core_agent_log_level": "info",
             "core_agent_permissions": 700,
             "core_agent_socket_path": "tcp://127.0.0.1:6590",
-            "core_agent_version": "v1.5.0",  # can be an exact tag name, or 'latest'
+            "core_agent_version": "v1.5.1",  # can be an exact tag name, or 'latest'
             "disabled_instruments": [],
             "download_url": (
                 "https://s3-us-west-1.amazonaws.com/scout-public-downloads/"