ci/Update container to atlas v0.38.1

[twsearle]

Description

Upgrade the CI container to use atlas 0.38.1 in container v1.3.0. Point the current CI to the container at atlas 0.37.0.

[twsearle]

@odlomax I think this setup I am experimenting with does what you wanted yesterday? - you can rebuild the container when you need to change the versions of some base packages, but you don't need to rebuild the container every time (container build takes 44 mins, ci takes 30 mins so I think its best not to roll into one set of actions that happens on every commit to a PR).

This is only a temporary solution, there are probably neater, nicer ways of working across the various Met Office repos. But its a proof of concept. It is also worth pointing out that the packages created are private to me - no-one can access my containers by default so I think its safe even for proprietary code (for now the image only contains open libraries).

[yaswant]

There is a version bump in this PR, are you not planning to use 1.3.0 or is this a chicken-and-egg problem?

[twsearle]

So this is the chicken and egg problem I am still figuring out. I actually realised I could combine this PR with #107 but not until after I had made it!

In this PR I update the container specification to v1.3.0 (containing atlas 0.38.1) but I keep the ci pegged at atlas 0.37.0 so that it still works with that version and will pass. At #107 I update the tests in orca-jedi for validity with 0.38.1, and I update to use the new container created by this PR (when I pushed the tag for v1.3.0)).

This is tricky to explain in text and I am happy to have a call if it helps! As I say, I think I could have combined the two PRs, but I did it this way because I was still understanding this stuff and wanted to make it clear that this PR only affects the container build, not orca-jedi, orca-jedi compatibility with atlas, or anything real - only #107 needs to be coordinated with the rest of mo-bundle changes.

[twsearle]

As for the reason for this specific line - I figured out that I can make tags even on my PRs - so the container in use on the previous PR should have originally read v1.2.0 as it was compatible with the VERSION of orca-jedi at v1.2.0.