Add log line grouping

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "gha"
-version = "0.1.3"
+version = "0.1.4"
 authors = ["Peter Nehrer <pnehrer@eclipticalsoftware.com>"]
 repository = "https://github.com/ecliptical/gha"
 description = """

src/group.rs

@@ -0,0 +1,18 @@
+//! [Grouping log lines](https://docs.github.com/en/actions/using-workflows/workflow-commands-for-github-actions#grouping-log-lines)
+
+/// Mark the start of the log line group.
+pub fn start_group(title: &str) {
+    println!("::group::{title}");
+}
+
+/// Mark the end of the log line group.
+pub fn end_group() {
+    println!("::endgroup::");
+}
+
+/// Perform arbitrary logic in the context of a log line group.
+pub fn group<F: FnOnce() -> ()>(title: &str, f: F) {
+    start_group(title);
+    f();
+    end_group();
+}

src/lib.rs

@@ -3,8 +3,10 @@
 mod env;
 mod file;
 mod func;
+mod group;
 mod message;
 
 pub use env::*;
 pub use file::*;
 pub use func::*;
+pub use group::*;