build(pip): migrate to pipenv

Dockerfile

@@ -13,10 +13,11 @@ ARG BUILD_DEPS="\
 
 RUN apk add --update --no-cache ${BUILD_DEPS}
 
-COPY requirements.txt requirements.txt
-RUN pip install -r requirements.txt
+COPY Pipfile* .
+RUN pip install pipenv && \
+    pipenv install --deploy --system
 
-FROM python:3.9.7-alpine3.14 AS runner
+FROM python:3.9.7-alpine3.14 AS runtime
 
 LABEL "maintainer"="Eugene Vasilenko <gmrnsk@gmail.com>"
 LABEL "repository"="https://github.com/gofrolist/molecule-action"

Pipfile

@@ -0,0 +1,16 @@
+[[source]]
+url = "https://pypi.org/simple"
+verify_ssl = true
+name = "pypi"
+
+[packages]
+flake8 = "==3.9.2"
+molecule-inspec = "==1.1"
+molecule = {version = "==3.4.1", extras = ["docker", "podman", "lint"]}
+testinfra = "==6.0.0"
+yamllint = "==1.26.3"
+
+[dev-packages]
+
+[requires]
+python_version = "3.9"