Add Style::set_dimmed to support dimmed text

Cargo.toml

@@ -23,7 +23,7 @@ members = [
 [dependencies]
 log = { version = "0.4.8", features = ["std"] }
 regex = { version = "1.0.3", optional = true, default-features=false, features=["std", "perf"] }
-termcolor = { version = "1.0.2", optional = true }
+termcolor = { version = "1.1.1", optional = true }
 humantime = { version = "2.0.0", optional = true }
 atty = { version = "0.2.5", optional = true }
 

src/fmt/writer/termcolor/extern_impl.rs

@@ -339,6 +339,33 @@ impl Style {
         self
     }
 
+    /// Set whether the text is dimmed.
+    ///
+    /// If `yes` is true then text will be written in a dimmer color.
+    /// If `yes` is false then text will be written in the default color.
+    ///
+    /// # Examples
+    ///
+    /// Create a style with dimmed text:
+    ///
+    /// ```
+    /// use std::io::Write;
+    ///
+    /// let mut builder = env_logger::Builder::new();
+    ///
+    /// builder.format(|buf, record| {
+    ///     let mut style = buf.style();
+    ///
+    ///     style.set_dimmed(true);
+    ///
+    ///     writeln!(buf, "{}", style.value(record.args()))
+    /// });
+    /// ```
+    pub fn set_dimmed(&mut self, yes: bool) -> &mut Style {
+        self.spec.set_dimmed(yes);
+        self
+    }
+
     /// Set the background color.
     ///
     /// # Examples