Bump MSRV to Rust 1.58.0

[badboy]

Approving, but it might be a good chance to replace .panic("{}", e) to .panic_any(e). Clippy suggested the latter but it caused errors in #221 on the old version. How about it?

rustc warns about panic!(err); being deprecated and either panic!("{}", e); orpanic_any!(e)to replace it. We hadpanic!(err)in a couple of places and I fixed those in #222 to usepanic!("{}", e)`. They are only in tests:

❯ rg 'panic.\("\{\}", err'
src/backend/impl_lmdb/arch_migrator.rs
773:                Err(err) => panic!("{}", err),
775:                    Err(err) => panic!("{}", err),

tests/env-lmdb.rs
1519:                Err(err) => panic!("{}", err),

tests/env-safe.rs
1242:                Err(err) => panic!("{}", err),

No point in touching those.

[saschanaz]

Ah yes, I somehow thought I saw more but I'm wrong 😬, sorry. Thanks for correcting me.