Fix CI

[eldruin]

The CI is currently broken. See for example here

[pdaj-atl]

I took a look at this and it seems that the original issue linked above no longer occurs (at least I couldn't recreate it).

There is still a CI issue with [build (1.65.0, x86_64-unknown-linux-gnu)] which fails due to a number of dependencies requiring newer versions of rustc than 1.65.0, e.g.:

package mio v1.0.4 cannot be built because it requires rustc 1.70 or newer, while the currently active rustc version is 1.65.0
package tokio-macros v2.5.0 cannot be built because it requires rustc 1.70 or newer, while the currently active rustc version is 1.65.0
package bstr v1.12.0 cannot be built because it requires rustc 1.73 or newer, while the currently active rustc version is 1.65.0
package backtrace v0.3.75 cannot be built because it requires rustc 1.82.0 or newer, while the currently active rustc version is 1.65.0

I managed to solve some of them by downgrading the versions in Cargo.toml:

tokio = { version = "=1.38.2", features = ["io-std", "net"], optional = true }
bstr = "=1.10.0"

However, I ran into a problem with the backtrace crate as a dependency of:

quicli v0.4.0 -> clap-verbosity-flag v0.2.0 -> failure v0.1.8 -> backtrace v0.3.75 (which requires rustc >1.82.0)

I notice that that backtrace is an optional dependency of failure (https://github.com/rust-lang-deprecated/failure/blob/master/Cargo.toml), so perhaps it can just be switched off?

Anyway, as this is my first issue, I thought I should get some direction at this point. Should I continue trying to tinker with the dependency versions or is it acceptable to increase the MSRV (it would need quite a jump) or something else? Thanks!