feat: Allow choosing bzip2 rust backend

[elichai]

Bzip2 has a feature flag for allowing a rust backend (See trifectatechfoundation/bzip2-rs#40 (comment))
this exposes that feature to users so they can easily compile to wasm32-unknown-unknown

[Pr0methean]

@elichai Is this still needed now that #352 is merged?

[elichai]

I think so, AFAIU it only touched deflate, not bzip2

[Pr0methean]

error: package libbz2-rs-sys v0.1.3 cannot be built because it requires rustc 1.82 or newer, while the currently active rustc version is 1.75.0

Is this increase in the MSRV actually necessary? If so, see the Cargo.toml for instructions on updating it. If not, I prefer to increase it as slowly as possible, even though 1.82 does meet the stable-for-6-months requirement.

[elichai]

Is this increase in the MSRV actually necessary? If so, see the Cargo.toml for instructions on updating it. If not, I prefer to increase it as slowly as possible, even though 1.82 does meet the stable-for-6-months requirement.

I can look more deeply into why libbz2-rs-sys requires Rust 1.82 and if I can reduce it, but do note that it only affects users that will activate this feature.

I can try to update the --all-features MSRV job to exclude this feature and test it in a seperate job, or maybe even integrate cargo-hack to properly permute the features combinations

[Pr0methean]

@elichai After merging from master, I get the following error:

package `zip` depends on `bzip2` with feature `libbz2-rs-sys` but `bzip2` does not have that feature.
 An optional dependency with that name exists, but that dependency uses the "dep:" syntax in the features table, so it does not have an implicit feature with that name.

Is this PR still needed given that bzip2-sys is optional in bzip2 0.6.0?