Support Rust 1.48.0 and test on Debian 11

[romanz]

Following #423

[Kixunil]

@romanz do you agree with waiting with this until at least one of these happens?

• 0.9.1 release of electrs (assuming non-emergency)
• Raspbian has rustc 1.48

[romanz]

Definitely, thanks for the heads up!

[Kixunil]

I'm not sure why other commits got mixed here, I believe MSRV bump was planned in 0.10, not 0.9? Also a nit, I think renaming the crate in Cargo.toml would have bean cleaner. (And easy to switch back if upstream version is sufficient.)

[romanz]

I deleted p2p branch, and rebased p2p-bullseye over master - so I guess GitHub got confused...

[romanz]

https://github.com/romanz/electrs/pull/455/checks?check_run_id=3818923414#step:7:90

 error: if let .. else expression looks like `matches!` macro
Error:    --> src/p2p.rs:260:5
    |
260 | /     if let Inventory::Block(_) = inv {
261 | |         true
262 | |     } else {
263 | |         false
264 | |     }
    | |_____^ help: try this: `matches!(inv, Inventory::Block(_))`

[Kixunil]

I think matches is available in 1.48. BTW I believe MSRV can (and IMO should) to be configured in clippy but I don't see it configured here.

[romanz]

If there are no objections, I plan to merge it soon :)
@xanoni @openoms @AaronDewes @tehelsper @lukechilds

[romanz]

BTW, we can still build electrs using Rust 1.41.1:

$ cargo +1.41.1 build --release

[AaronDewes]

Not sure about the other, but I'm using an even later rust & bullseye to build anyway.

[openoms]

the later rust version is available for raspiblitz also, so will be built with the version set for cargo. No objections.