chore(setup): add b3 propagator as dependency for tests

Author: Div95

propagator/opentelemetry-propagator-env/setup.cfg

@@ -43,7 +43,7 @@ install_requires =
     opentelemetry-api ~= 1.3
 
 [options.extras_require]
-test =
+test = opentelemetry-propagator-b3
 
 [options.packages.find]
 where = src