`audit` action ignores lockfile

[jyn514]

cc @Kixiron - the audit action just started failing in https://github.com/rust-lang/docs.rs/runs/2006983845?check_suite_focus=true, but it should have been failing a long time earlier: #1295.

[Nemo157]

Looks like actions-rs/audit-check#163

[jyn514]

Thanks, I'll close this in favor of the upstream issue then.