Add a lockfile

[clux]

From a blank build today. I personally think this makes sense.

Reasons;

• basically https://blog.rust-lang.org/2023/08/29/committing-lockfiles.html
• frequently we get cargo deny issues pulled in from under us which we have to explain away
• contributor confusion; why does this not build? we don't want them to be the first to notice a breaking build, that's CIs job
• we can setup dependabot to auto-merge non-breaking changes that pass CI

Downsides:

• we still have to manually fix up most cargo deny issues
• we will get a lot more dependency prs, but if most are auto-merged then it should be ok? they don't show up in the github releases because of our changelog configuration

AFAIU non-breaking builds do not need to get pins updated from Cargo.toml so this should mostly be a sanity thing for CI and contributors (rather than forcing everyone to bump the dependencies of us).

Have setup automatic dependency merging in all other kube repos, but those are binaries so it's less scary / controversial. My experience with these have been very positive however, so feel we should probably do this here also.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 72.1%. Comparing base (5813ad0) to head (01dec7f).
⚠️ Report is 571 commits behind head on main.

Additional details and impacted files

@@          Coverage Diff          @@
##            main   #1337   +/-   ##
=====================================
  Coverage   72.1%   72.1%           
=====================================
  Files         75      75           
  Lines       6377    6377           
=====================================
  Hits        4597    4597           
  Misses      1780    1780           

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[Dav1dde]

Re: dependabot, I feel like there should be just a weekly lockfile maintenance which bumps the lockfile to the max dependency versions and not for each dependency individually

[clux]

We can do that I believe; weekly interval on dependabot with a grouping on "*"

[nightkr]

Very 👍 on this from me.

[clux]

I think this is nice personally also, but we could also get a decent approximation of safety with a daily build.

so a couple of things that would be good to get feelings on;

• lockfile safety vs. cron'd check of latest (cargo update + build)
• bump frequency / dependabot grouping setup / automerging (if using lockfile)
• MSRV implications (if we tail latest with a lockfile, then maybe we change msrv test to use -Zminimal-versions builds? - maybe we should do that anyway)

Feel free to leave comments here, but have also added it as an agenda item for tomorrow's meeting :-)

[nightkr]

Why not both?