Fix dependencies for test utils (open-telemetry#2587)

Author: lzchen

Diff for: tests/opentelemetry-test-utils/setup.cfg

@@ -40,9 +40,10 @@ packages=find_namespace:
 install_requires =
     opentelemetry-api ~= 1.3
     opentelemetry-sdk ~= 1.3
+    asgiref ~= 3.0
 
 [options.extras_require]
-test = flask~=2.0
+test =
 
 [options.packages.find]
 where = src

Diff for: tox.ini

@@ -198,6 +198,9 @@ commands_pre =
   python -m pip install -e {toxinidir}/opentelemetry-api[test]
   python -m pip install -e {toxinidir}/opentelemetry-semantic-conventions[test]
   python -m pip install -e {toxinidir}/opentelemetry-sdk[test]
+  # Pin protobuf version due to lint failing on v3.20.0
+  # https://github.com/protocolbuffers/protobuf/issues/9730
+  python -m pip install protobuf==3.19.4
   python -m pip install -e {toxinidir}/opentelemetry-proto[test]
   python -m pip install -e {toxinidir}/tests/opentelemetry-test-utils[test]
   python -m pip install -e {toxinidir}/shim/opentelemetry-opentracing-shim[test]