uucore: make chrono, chrono-tz, iana-time-zone deps optional under the custom-tz-fmt feature

Author: RenjiSann

src/uucore/Cargo.toml

@@ -21,17 +21,16 @@ all-features = true
 path = "src/lib/lib.rs"
 
 [dependencies]
-chrono = { workspace = true }
-chrono-tz = { workspace = true }
+chrono = { workspace = true, optional = true }
+chrono-tz = { workspace = true, optional = true }
 clap = { workspace = true }
 uucore_procs = { workspace = true }
 number_prefix = { workspace = true }
 dns-lookup = { workspace = true, optional = true }
 dunce = { version = "1.0.4", optional = true }
 wild = "2.2.1"
 glob = { workspace = true }
-iana-time-zone = { workspace = true }
-# * optional
+iana-time-zone = { workspace = true, optional = true }
 itertools = { workspace = true, optional = true }
 thiserror = { workspace = true, optional = true }
 time = { workspace = true, optional = true, features = [
@@ -134,6 +133,6 @@ utf8 = []
 utmpx = ["time", "time/macros", "libc", "dns-lookup"]
 version-cmp = []
 wide = []
-custom-tz-fmt = []
+custom-tz-fmt = ["chrono", "chrono-tz", "iana-time-zone"]
 tty = []
 uptime = ["libc", "windows-sys", "utmpx", "utmp-classic", "thiserror"]