try use base alpine instead of python image

Dockerfile

@@ -1,7 +1,7 @@
 ARG PYTHON_VERSION
 ARG ALPINE_VERSION
 
-FROM python:${PYTHON_VERSION}-alpine AS builder
+FROM alpine:${ALPINE_VERSION} AS builder
 
 ARG VERSION
 ARG CHECKSUM
@@ -23,7 +23,7 @@ RUN LD_PRELOAD=libgcompat.so.0 duoauthproxy-build/install --install-dir /app --s
 RUN rm -rf /app/usr/local/lib/python${PYTHON_VERSION%.*}/test
 RUN chown -R nobody:nobody /app/conf
 
-FROM alpine:edge
+FROM alpine:${ALPINE_VERSION}
 WORKDIR /app
 RUN apk add --no-cache libgcc libffi-dev gcompat su-exec
 USER 0:0