Porter should not pin to debian stretch

[carolynvs]

When porter create is run, it uses debian:stretch-slim as the base image. This image was just archived and now porter build fails with the following error when used with the default bundle created by porter.

We should use stable instead of a specific release of debian to avoid this problem going forward.

$ porter build
...
Building invocation image
...
------
 > [stage-0  4/10] RUN --mount=type=cache,target=/var/cache/apt --mount=type=cache,target=/var/lib/apt     apt-get update && apt-get install -y ca-certificates:
#0 0.592 Ign:1 http://security.debian.org/debian-security stretch/updates InRelease
#0 0.614 Ign:2 http://security.debian.org/debian-security stretch/updates Release
#0 0.615 Ign:3 http://deb.debian.org/debian stretch InRelease
#0 0.634 Ign:4 http://security.debian.org/debian-security stretch/updates/main all Packages
#0 0.636 Ign:5 http://deb.debian.org/debian stretch-updates InRelease
#0 0.650 Ign:6 http://security.debian.org/debian-security stretch/updates/main amd64 Packages
#0 0.659 Ign:7 http://deb.debian.org/debian stretch Release
#0 0.666 Ign:4 http://security.debian.org/debian-security stretch/updates/main all Packages
#0 0.681 Ign:6 http://security.debian.org/debian-security stretch/updates/main amd64 Packages
#0 0.685 Ign:8 http://deb.debian.org/debian stretch-updates Release
#0 0.700 Ign:4 http://security.debian.org/debian-security stretch/updates/main all Packages
#0 0.707 Ign:9 http://deb.debian.org/debian stretch/main amd64 Packages
#0 0.718 Ign:6 http://security.debian.org/debian-security stretch/updates/main amd64 Packages
#0 0.731 Ign:10 http://deb.debian.org/debian stretch/main all Packages
#0 0.735 Ign:4 http://security.debian.org/debian-security stretch/updates/main all Packages
#0 0.749 Ign:6 http://security.debian.org/debian-security stretch/updates/main amd64 Packages
#0 0.757 Ign:11 http://deb.debian.org/debian stretch-updates/main all Packages
#0 0.765 Ign:4 http://security.debian.org/debian-security stretch/updates/main all Packages
#0 0.778 Ign:12 http://deb.debian.org/debian stretch-updates/main amd64 Packages
#0 0.784 Ign:6 http://security.debian.org/debian-security stretch/updates/main amd64 Packages
#0 0.800 Ign:4 http://security.debian.org/debian-security stretch/updates/main all Packages
#0 0.802 Ign:9 http://deb.debian.org/debian stretch/main amd64 Packages
#0 0.817 Err:6 http://security.debian.org/debian-security stretch/updates/main amd64 Packages
#0 0.817   404  Not Found [IP: 151.101.2.132 80]
#0 0.824 Ign:10 http://deb.debian.org/debian stretch/main all Packages
#0 0.851 Ign:11 http://deb.debian.org/debian stretch-updates/main all Packages
#0 0.875 Ign:12 http://deb.debian.org/debian stretch-updates/main amd64 Packages
#0 0.900 Ign:9 http://deb.debian.org/debian stretch/main amd64 Packages
#0 0.925 Ign:10 http://deb.debian.org/debian stretch/main all Packages
#0 0.949 Ign:11 http://deb.debian.org/debian stretch-updates/main all Packages
#0 0.974 Ign:12 http://deb.debian.org/debian stretch-updates/main amd64 Packages
#0 0.999 Ign:9 http://deb.debian.org/debian stretch/main amd64 Packages
#0 1.020 Ign:10 http://deb.debian.org/debian stretch/main all Packages
#0 1.044 Ign:11 http://deb.debian.org/debian stretch-updates/main all Packages
#0 1.069 Ign:12 http://deb.debian.org/debian stretch-updates/main amd64 Packages
#0 1.094 Ign:9 http://deb.debian.org/debian stretch/main amd64 Packages
#0 1.118 Ign:10 http://deb.debian.org/debian stretch/main all Packages
#0 1.143 Ign:11 http://deb.debian.org/debian stretch-updates/main all Packages
#0 1.170 Ign:12 http://deb.debian.org/debian stretch-updates/main amd64 Packages
#0 1.195 Err:9 http://deb.debian.org/debian stretch/main amd64 Packages
#0 1.195   404  Not Found
#0 1.259 Ign:10 http://deb.debian.org/debian stretch/main all Packages
#0 1.283 Ign:11 http://deb.debian.org/debian stretch-updates/main all Packages
#0 1.308 Err:12 http://deb.debian.org/debian stretch-updates/main amd64 Packages
#0 1.308   404  Not Found
#0 1.324 Reading package lists...
#0 1.402 W: The repository 'http://security.debian.org/debian-security stretch/updates Release' does not have a Release file.
#0 1.403 W: The repository 'http://deb.debian.org/debian stretch Release' does not have a Release file.
#0 1.403 W: The repository 'http://deb.debian.org/debian stretch-updates Release' does not have a Release file.
#0 1.403 E: Failed to fetch http://security.debian.org/debian-security/dists/stretch/updates/main/binary-amd64/Packages  404  Not Found [IP: 151.101.2.132 80]
#0 1.403 E: Failed to fetch http://deb.debian.org/debian/dists/stretch/main/binary-amd64/Packages  404  Not Found
#0 1.403 E: Failed to fetch http://deb.debian.org/debian/dists/stretch-updates/main/binary-amd64/Packages  404  Not Found
#0 1.403 E: Some index files failed to download. They have been ignored, or old ones used instead.
------
error building docker image: failed to solve: executor failed running [/bin/sh -c apt-get update && apt-get install -y ca-certificates]: exit code: 100
unable to build CNAB invocation image: error building docker image: failed to solve: executor failed running [/bin/sh -c apt-get update && apt-get install -y ca-certificates]: exit code: 100

[carolynvs]

To workaround this, use a custom Dockerfile and change the base image from stretch to stable:

https://getporter.org/custom-dockerfile/

# Default base image, doesn't work anymore
FROM --platform=linux/amd64 debian:stretch-slim

# Switch to the stable release of debian
FROM --platform=linux/amd64 debian:stable-slim