Add missing typing-extensions dependency

Thanks @itsthejoker for reporting.

Author: PeterJCLaw

poetry.lock

@@ -18,6 +18,7 @@ python = ">=3.6.1,<4"
 django = ">=2.2"
 daemonize = "~=2.5.0"
 prometheus-client = "~=0.7"
+typing-extensions = "^4"
 redis = {version = "~=3.*", optional = true}
 tqdm = {version = "^4.54.1", optional = true}