Don't depend on flake8 at runtime

Instead move running flake8 to our lint job and keep that dependency on
a `requirements.txt` file in the repository root.

.github/workflows/ci.yml

@@ -210,4 +210,9 @@ jobs:
       - uses: ruby/setup-ruby@v1
         with:
           bundler-cache: true
+      - uses: actions/setup-python@v1
+        with:
+          python-version-file: .python-version
+          cache: pip
+      - run: pip install -r requirements.txt
       - run: ./bin/lint

.python-version

@@ -0,0 +1 @@
+3.7

bin/lint

@@ -15,3 +15,5 @@ shellcheck \
   "$@"
 
 bundle exec rubocop
+
+flake8 python/helpers/. --count --exclude=./.*,./python/spec/fixtures --show-source --statistics

python/helpers/requirements.txt

@@ -1,6 +1,5 @@
 pip>=21.3.1,<23.1.0  # Range maintains py36 support TODO: Review python 3.6 support in April 2023 (eol ubuntu 18.04)
 pip-tools>=6.4.0,<=6.12.3  # Range maintains py36 support TODO: Review python 3.6 support in April 2023 (eol ubuntu 18.04)
-flake8==5.0.4
 hashin==0.17.0
 pipenv==2022.4.8
 pipfile==0.0.2

python/script/ci-test

@@ -3,5 +3,4 @@
 set -e
 
 bundle install
-pyenv exec flake8 helpers/. --count --exclude=./.*,./python/spec/fixtures --show-source --statistics
 bundle exec parallel_test spec/ -n "$CI_NODE_TOTAL" --only-group "$CI_NODE_INDEX" --group-by filesize --type rspec

requirements.txt

@@ -0,0 +1 @@
+flake8==5.0.4