[CI] Re-enable python2 flake8 checking (#1591)

This was accidentally removed in #1183

.circleci/config.yml

@@ -78,13 +78,24 @@ jobs:
     steps:
       - checkout
       - run:
-          name: install pip
+          name: install python deps
           command: |
             apt-get update -q
-            apt-get install -q -y python3-pip
-      - run: python3 -m pip install --upgrade pip
-      - run: python3 -m pip install flake8==7.1.1
-      - run: python3 -m flake8 --show-source --statistics --extend-exclude=./scripts
+            apt-get install -q -y python2 python3-pip
+      - run:
+          name: python2 flake8
+          command: |
+            curl https://bootstrap.pypa.io/pip/2.7/get-pip.py --output get-pip.py
+            python2 get-pip.py
+            python2 -m pip install flake8==3.9.2
+            python2 -m flake8 --show-source --statistics --extend-exclude=./scripts
+      - run:
+          name: python3 flake8
+          command: |
+            python3 -m pip install --upgrade pip
+            python3 -m pip install flake8==7.1.1
+            python3 -m flake8 --show-source --statistics --extend-exclude=./scripts
+
 
   test-linux:
     executor: ubuntu