I recommend to use Python 3.x since Python 2.x is deprecated!
Installing python-config for Python 3.x
The python3-dev apk package provides /usr/bin/python3-config, so you’ll have to symlink that to /usr/bin/python-config:
apk update apk add python3-dev ln -sf /usr/bin/python3-config /usr/bin/python-config
Installing python-config for Python 2.x
Just install python2-dev, which installs /usr/bin/python-config
apk update apk add python2-dev