Log dependency fix makes use as library very hard

[stevenroose]

bdk depends on log = "=0.4.18", which is really annoying for anyone having another version of log in their dependency tree.

[LLFourn]

Looks like this was done in #1009. I think the correct solution is to just pin the version in CI using a CI specific Cargo.lock?

On a side note I'd be in favor of not using log throughout the codebase as I don't find it very helpful as an app developer but maybe that's just me.

[tnull]

Looks like this was done in #1009. I think the correct solution is to just pin the version in CI using a CI specific Cargo.lock?

I think other project (LDK, rust-bitcoin) just have a msrv flag in CI and pin the respective dependencies based on it, i.e., we just run this in CI:

	[ "$RUSTC_MINOR_VERSION" -lt 49 ] && cargo update -p log --precise "0.4.18" --verbose

(see https://github.com/lightningdevkit/rust-lightning/blob/8a8f29a8bb970ef99137db7233ca85e1a2406b7a/ci/ci-tests.sh#L16)

[danielabrozzoni]

Sorry, when I pinned log I didn't realize it could be an issue for downstream projects. #1046 should fix :)