ci: bump pinned Rust to 1.70

[iamwacko]

Description of change

Closes #964

[iamwacko]

cimg/rust hasn't been bumped to 1.70 yet. Would it be better to wait for the bump or switch images?

[AliSajid]

cimg-rust#110 Has that image coming up. Could be a moot point.

[iamwacko]

I made a whole bunch of commits thinking changes I had made were causing the rocket tests to fail, but now that I took a look at the tests in main I see that all that effort was for nothing. That also means that this should be ready to merge.

[oddgrd]

Apologies again for the CI confusion!

I left a comment about the clippy lint, I think we should rather refactor it. If we do ignore a clippy lint we should leave a comment about why as well. Regarding the once_cell that's fine, we can do it in a separate PR/later when the LazyCell equivalent is stabilized.

[iamwacko]

#821 strikes again, with a side of errors of unknown cause. I'm getting the error below for all of deployment::deploy_layer::tests.

thread 'thread 'deployment::deploy_layer::tests::deployment_main_panicdeployment::deploy_layer::tests::deployment_bind_panic' panicked at '' panicked at 'states should go into 'Crashed' when panicking in main: [

[oddgrd]

LGTM, thanks for this @iamwacko! I believe the deployer tests are spurious and not related to this PR.

[iulianbarbu]

LGTM! Thanks @iamwacko !

[iulianbarbu]

nit: running a cargo sort might put the dep here again.