Remove stringcase dependency

Author: boukeversteegh

poetry.lock

@@ -18,7 +18,6 @@ dataclasses = { version = "^0.7", python = ">=3.6, <3.7" }
 grpclib = "^0.3.1"
 jinja2 = { version = "^2.11.2", optional = true }
 protobuf = { version = "^3.12.2", optional = true }
-stringcase = "^1.2.0"
 
 [tool.poetry.dev-dependencies]
 black = "^19.10b0"