Update fs-err requirement from 2 to 3 (#51)

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

docker/build-libunwind/Cargo.toml

@@ -4,7 +4,7 @@ edition = "2021"
 
 [dependencies]
 cc = "1"
-fs-err = "2"
+fs-err = "3"
 
 [lints.rust]
 rust_2018_idioms = "warn"