Add used pytest markers to pyproject.toml

This prevents pytest from complaining about unregistered markers

Author: gfrances

pyproject.toml

@@ -14,3 +14,8 @@ include = '\.pyi?$'
 log_format = "%(asctime)s %(levelname)s %(message)s"
 log_date_format = "%Y-%m-%d %H:%M:%S"
 addopts = "-rsxX -q"
+
+markers = [
+    "pddl",
+    "sas",
+]