deps(common/log): drop env_logger's auto-color and regex features

#2291 added additional formatting to our log
output via `env_logger`'s `auto-color` feature. The `auto-color` feature adds
the `is-terminal` crate dependency. `is-terminal` depends on `hermit-abi`
`v0.4`.

Pulling latest Neqo `v0.12.0` into mozilla-central adds `is-terminal` and
`hermit-abi` `v0.4.0` to the Firefox dependency tree.

In order to keep our dependency footprint low, I suggest not enabling the two
`env-logger` features.

neqo-common/Cargo.toml

@@ -18,7 +18,7 @@ workspace = true
 [dependencies]
 # Checked against https://searchfox.org/mozilla-central/source/Cargo.lock 2024-11-11
 enum-map = { workspace = true }
-env_logger = { version = "0.10", default-features = false, features = ["auto-color", "regex"] }
+env_logger = { version = "0.10", default-features = false }
 hex = { version = "0.4", default-features = false, features = ["alloc"], optional = true }
 log = { workspace = true }
 qlog = { workspace = true }

neqo-common/src/log.rs

@@ -33,18 +33,12 @@ pub fn init(level_filter: Option<log::LevelFilter>) {
         }
         builder.format(|buf, record| {
             let elapsed = since_start();
-            let level_style = buf.default_level_style(record.level());
-            let mut bold = buf.style();
-            bold.set_bold(true);
             writeln!(
                 buf,
-                "{} {} {}",
-                bold.value(format!(
-                    "{}.{:03}",
-                    elapsed.as_secs(),
-                    elapsed.as_millis() % 1000
-                )),
-                level_style.value(record.level()),
+                "{}.{:03} {} {}",
+                elapsed.as_secs(),
+                elapsed.as_millis() % 1000,
+                record.level(),
                 record.args()
             )
         });