Add example in workspace root for git_submodule_versions!().

git-version/README.md

@@ -13,4 +13,14 @@ untracked or changed files.
 These macros do not depend on libgit, but simply uses the `git` binary directly.
 So you must have `git` installed somewhere in your `PATH`.
 
+You can also get the version information for all submodules:
+```rust
+use git_version::git_submodule_versions;
+const GIT_SUBMODULE_VERSIONS: &[(&str, &str)] = &git_submodule_versions!();
+
+for (path, version) in GIT_SUBMODULE_VERSIONS {
+    println!("{path}: {version}");
+}
+```
+
 License: BSD-2-Clause

git-version/src/lib.rs

@@ -12,6 +12,16 @@
 //!
 //! These macros do not depend on libgit, but simply uses the `git` binary directly.
 //! So you must have `git` installed somewhere in your `PATH`.
+//!
+//! You can also get the version information for all submodules:
+//! ```
+//! use git_version::git_submodule_versions;
+//! const GIT_SUBMODULE_VERSIONS: &[(&str, &str)] = &git_submodule_versions!();
+//!
+//! for (path, version) in GIT_SUBMODULE_VERSIONS {
+//!     println!("{path}: {version}");
+//! }
+//! ```
 
 pub use git_version_macro::{git_submodule_versions, git_version};