Change baseimage for node:slim to stretch release

[mkumatag]

Fixes: #821

[mkumatag]

/cc @PeterDaveHello

[PeterDaveHello]

/cc @nodejs/docker

[mkumatag]

We don't directly update the Dockerfile, instead, we need to update the templates at the root of the repository.

I suggest to make decision at the issue, and after that, send the pull request.

How it works? I see those 2 packages are missing, so do you want me to create a separate template called Dockerfile-slim-stretch.template or something?

[PeterDaveHello]

I suppose we should discuss before making changes, let's move back to the issue.

[LaurentGoderre]

I think the changes have to be made to the following file:

https://github.com/nodejs/docker-node/blob/master/Dockerfile-slim.template

Then the update will be picked up on next release.

[mkumatag]

@LaurentGoderre can you drop your suggestion in #821 ?

[chorrell]

Would it be better to just have a separate stretch-slim variant rather than modifying the current slim variant? I'm thinking we should treat it like we do with the default variant.

[mkumatag]

@PeterDaveHello@LaurentGoderre I just made suggested changes, PTAL and let me know if anything else is required.?

[LaurentGoderre]

@chorrell do you mean we'd have a stretch-slim and a jessy-slim?

[chorrell]

Yeah

[kbirger]

@PeterDaveHello are your requests satisfied? Seems like this could be merged now.

[LaurentGoderre]

I opened #850 as an alternative for a smoother transition.

[LaurentGoderre]

Closing as this was addressed via #850