fix build

[zoedberg]

As reported in RGB-WG/rgb-node#224 (comment) documentation of lnp-core doesn't build on docs.rs (https://docs.rs/crate/lnp-core/0.8.0/builds/592909).

Cloning the repository locally and running cargo build produces the same error logs we see on docs.rs. Adding bifrost to the default features of lnp2p seems to fix the build.

@dr-orlovsky if you think this fix is appropriate then you can release this first and rgb-node after. Thank you

[codecov-commenter]

Codecov Report

Merging #17 (6b58060) into master (9e235c0) will decrease coverage by 3.3%.
The diff coverage is 26.5%.

@@           Coverage Diff            @@
##           master     #17     +/-   ##
========================================
- Coverage    37.7%   34.4%   -3.3%     
========================================
  Files          20      17      -3     
  Lines        1757    1883    +126     
========================================
- Hits          662     647     -15     
- Misses       1095    1236    +141     

Impacted Files	Coverage Δ
lnp2p/src/bifrost/app.rs	0.0% <0.0%> (ø)
lnp2p/src/bifrost/channel.rs	0.0% <0.0%> (ø)
lnp2p/src/bifrost/msg.rs	0.0% <0.0%> (ø)
lnp2p/src/bifrost/proposals.rs	0.0% <0.0%> (ø)
lnp2p/src/bolt/bolt1.rs	50.0% <0.0%> (ø)
lnp2p/src/bolt/bolt11.rs	0.0% <0.0%> (ø)
lnp2p/src/bolt/bolt2.rs	10.6% <0.0%> (ø)
lnp2p/src/bolt/bolt4.rs	0.0% <0.0%> (ø)
lnp2p/src/bolt/bolt7.rs	0.0% <0.0%> (ø)
lnp2p/src/bolt/bolt9.rs	52.7% <0.0%> (ø)
... and 9 more

📣 We’re building smart automated test selection to slash your CI/CD build times. Learn more

[dr-orlovsky]

It seems that the problem was caused by releasing the library without --all-features. What you propose is to enable all features by default, which is incorrect (it is ok for the crate to have a non-default features; a lot of such crates build on docs.rs). I will try to do a release with --all-features and nothing else changed - lets see would it help. Another option is to add

[package.metadata.docs.rs]
features = ["all"]

to the Cargo.toml, which I think will be a good solution for all our crates

[dr-orlovsky]

Closing in favor of e25d73d