Add tox runs for multiple dependency configurations, and fix dependency version conflicts

Author: benjaminran

Makefile

@@ -11,7 +11,7 @@ develop:
 
 tests:
 	# skipping flake8 for now
-	pip3 install --upgrade --quiet tox && tox -p 4 -e py36,py37,py38,py39
+	pip3 install --upgrade --quiet tox && TOX_SKIP_ENV='flake|docs' tox
 
 docs:
 	echo skipping temporarily...

requirements.txt

@@ -6,4 +6,4 @@ sentry-sdk>=1.0.0
 dnspython>=2.0.0
 # openapi generated client:
 python_dateutil >= 2.5.3
-urllib3 >= 1.25.3
+urllib3 >= 1.21.1

tox.ini

@@ -1,13 +1,21 @@
 [tox]
-envlist = py{36,37,38,39},flake8,docs
+envlist = py{36,37,38,39}-pcgrpc_{yes,no}-old_deps_{yes,no},flake8,docs
 skip_missing_interpreters = true
 
 [testenv]
 setenv = HOSTNAME=hostname
 deps=
+  old_deps_yes: requests==2.19.0
+  old_deps_yes: pyyaml==5.4
+  old_deps_yes: loguru==0.5.0
+  old_deps_yes: typing-extensions==3.7.4
+  old_deps_yes: sentry-sdk==1.0.0
+  old_deps_yes: dnspython==2.0.0
+  old_deps_yes: python_dateutil==2.5.3
+  old_deps_yes: urllib3==1.21.1
   -r {toxinidir}/requirements.txt
-  -r {toxinidir}/requirements-grpc.txt
   -r {toxinidir}/test-requirements.txt
+  pcgrpc_yes: -r {toxinidir}/requirements-grpc.txt
 commands =
   pytest --cov=pinecone --timeout=120 tests/unit {posargs}