fix(deps): update dependency voluptuous to ^0.15.0

Author: renovate[bot]

agent/pyproject.toml

@@ -10,7 +10,7 @@ python = "^3.8"        # specify your Python version requirement here
 influxdb = "^5.3.2"
 pyyaml = "^6.0.1"
 requests = "^2.31.0"
-voluptuous = "^0.14.2"
+voluptuous = "^0.15.0"
 testflinger-common = { path = "../common" }
 
 [tool.poetry.dev-dependencies]