feat: add workspace example with foo and utils packages

examples/r5/workspace-example/Cargo.toml

@@ -0,0 +1,6 @@
+[workspace]
+
+members = [
+    "utils",
+    "foo"
+]

examples/r5/workspace-example/foo/Cargo.toml

@@ -0,0 +1,7 @@
+[package]
+name = "foo"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+utils = { path = "../utils" }

examples/r5/workspace-example/foo/src/main.rs

@@ -0,0 +1,5 @@
+use utils::add;
+
+fn main() {
+    println!("{:?}", add(1, 2));
+}

examples/r5/workspace-example/utils/Cargo.toml

@@ -0,0 +1,6 @@
+[package]
+name = "utils"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]

examples/r5/workspace-example/utils/src/lib.rs

@@ -0,0 +1,14 @@
+pub fn add(left: u64, right: u64) -> u64 {
+    left + right
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn it_works() {
+        let result = add(2, 2);
+        assert_eq!(result, 4);
+    }
+}