Update pyproject.toml to rm deprecated argument

Author: pamelafox

pyproject.toml

@@ -3,7 +3,6 @@ line-length = 120
 target-version = "py311"
 select = ["E", "F", "I", "UP"]
 ignore = ["D203"]
-show-source = true
 
 [tool.black]
 line-length = 120