chore: Various development improvements.

Preparing possibility of `3.0.0b0-py37` & `3.0.0b0-py36` releases.

Author: playpauseandstop

CHANGELOG.md

@@ -4,7 +4,8 @@
 
 - **Breaking change:** Make `py38` default image
 - **Breaking change:** Install `poetry==1.0.0b4` for all images
-- **Breaking change:** Use `slim-buster` image for `py35`, `py36`, and `py37`
+- **Breaking change:** Use `slim-buster` image for `py37` & `py36` as well
+- **Breaking change:** Drop support of `py35` images
 - Simplify development by introducing `Makefile`
 
 # 2.0.0 (2019-10-29)

Makefile

@@ -2,12 +2,13 @@
 
 DOCKER ?= docker
 IMAGE ?= playpauseandstop/docker-python
+VERSION ?= latest
 
 all: build
 
 build: .build
 .build: Dockerfile
-	$(DOCKER) build -t $(IMAGE) .
+	$(DOCKER) build -t $(IMAGE):$(VERSION) .
 	touch $@
 
 deploy:

README.md

@@ -38,6 +38,8 @@ List of supported Python versions are (`<PY_VERSION>` -> base Docker image):
 #### 3.0.0b0
 
 - `py38` -> `python:3.8.0-slim-buster`
+- `py37` -> `python:3.7.5-slim-buster`
+- `py36` -> `python:3.6.9-slim-buster`
 
 #### 2.0.0