base-python dependency python3 pin version is no longer valid

[LanceEa]

Summary

Alpine Package Manager appears to only make available a single patch version for its dependency. A recent update to the python3 version caused the base-python image to be rebuilt and it failed due to our pinned version not being available.

pinned version: =~3.9.7 APK version: 3.9.13-r1

#12 [ambassador  3/24] RUN apk --no-cache add bash curl python3=~3.9.7 libcap htop
#12 sha256:d33047370f4abbf33b41036d4afed6686730ac47677e4150380741ef10f6a783
#12 0.699 fetch https://dl-cdn.alpinelinux.org/alpine/v3.15/main/x86_64/APKINDEX.tar.gz
#12 0.895 fetch https://dl-cdn.alpinelinux.org/alpine/v3.15/community/x86_64/APKINDEX.tar.gz
#12 1.228 ERROR: unable to select packages:
#12 1.277   python3-3.9.13-r1:
#12 1.277     breaks: world[python3~3.9.7]
#12 ERROR: executor failed running [/bin/sh -c apk --no-cache add bash curl python3=${py_version} libcap htop]: exit code: 1

Based on the r1 it appears that APK is being updated with release candidates so this will probably occur a few times until the official 3.9.13 lands.

https://pkgs.alpinelinux.org/packages?name=python3&branch=v3.15&repo=main&arch=x86_64

To Reproduce Look at this CI run: https://github.com/emissary-ingress/emissary/runs/7539393555?check_suite_focus=true

Expected behavior base-python should be able to build properly when Alpine Package Manager updates its patch version.