Update pinned pip version to match core st2

Core st2 has pip==20.0.2 pinned. Also, virtualenv is building the env
with a much newer version of pip now.

So, the CI is flapping back and forth between pip-9.0*, pip-20.0*, and
pip-20.3* (the latest right now).

st2 pinned version is here:
https://github.com/StackStorm/st2/blob/v3.3/Makefile#L56

Author: cognifloyd

.circle/Makefile

@@ -283,7 +283,7 @@ requirements: virtualenv .clone_st2_repo .install-runners
 	@echo
 	@echo "==================== requirements ===================="
 	@echo
-	. $(VIRTUALENV_DIR)/bin/activate && $(VIRTUALENV_DIR)/bin/pip install --upgrade "pip>=9.0,<9.1"
+	. $(VIRTUALENV_DIR)/bin/activate && $(VIRTUALENV_DIR)/bin/pip install --upgrade "pip==20.0.2"
 	. $(VIRTUALENV_DIR)/bin/activate && $(VIRTUALENV_DIR)/bin/pip install --cache-dir $(HOME)/.pip-cache -q -r $(CI_DIR)/.circle/requirements-dev.txt
 	. $(VIRTUALENV_DIR)/bin/activate && $(VIRTUALENV_DIR)/bin/pip install --cache-dir $(HOME)/.pip-cache -q -r $(CI_DIR)/.circle/requirements-pack-tests.txt
 
@@ -292,7 +292,7 @@ requirements-ci:
 	@echo
 	@echo "==================== requirements-ci ===================="
 	@echo
-	. $(VIRTUALENV_DIR)/bin/activate && $(VIRTUALENV_DIR)/bin/pip install --upgrade "pip>=9.0,<9.1"
+	. $(VIRTUALENV_DIR)/bin/activate && $(VIRTUALENV_DIR)/bin/pip install --upgrade "pip==20.0.2"
 	. $(VIRTUALENV_DIR)/bin/activate && $(VIRTUALENV_DIR)/bin/pip install --cache-dir $(HOME)/.pip-cache -q -r $(CI_DIR)/.circle/requirements-dev.txt
 	. $(VIRTUALENV_DIR)/bin/activate && $(VIRTUALENV_DIR)/bin/pip install --cache-dir $(HOME)/.pip-cache -q -r $(CI_DIR)/.circle/requirements-pack-tests.txt
 

.circle/dependencies

@@ -38,11 +38,17 @@ sudo apt-get -y install libldap2-dev libsasl2-dev
 # Hit github's API to keep the PAT active (without failing if it's not)
 (GH_TOKEN=${MACHINE_PASSWORD} gh repo view | head -n2) || true
 
-sudo pip install -U "pip>=9.0,<9.1" setuptools virtualenv
+# This should track the pinned version of pip in st2's Makefile
+PIP_DEP="pip==20.0.2"
+sudo pip install -U "${PIP_DEP}" setuptools virtualenv
 
 virtualenv ~/virtualenv
 source ~/virtualenv/bin/activate
 
+# virtualenv is updating pip. Revert back to our pinned version.
+pip install -U "${PIP_DEP}"
+pip --version
+
 # Install StackStorm requirements
 echo "Installing StackStorm requirements from /tmp/st2/requirements.txt"
 ~/virtualenv/bin/pip install -r "/tmp/st2/requirements.txt"

.circleci/config.yml

@@ -21,7 +21,7 @@ jobs:
           name: Download and Install Dependencies
           command: |
             git clone --depth 1 --single-branch --branch "${LINT_CONFIGS_BRANCH:-master}" https://github.com/StackStorm/lint-configs.git ~/ci/lint-configs
-            sudo pip install -U "pip>=9.0,<9.1" setuptools virtualenv pyyaml
+            sudo pip install -U "pip==20.0.2" setuptools virtualenv pyyaml
             virtualenv ~/virtualenv
             ~/virtualenv/bin/pip install flake8 pylint pyyaml requests
       - save_cache: