README: Add more Rust vendoring examples (using different approaches)

README.md

@@ -620,9 +620,13 @@ RULE:     packages will be used to build).
 RULE:   - The tooling to get a Cargo.lock that will include internal vendored
 RULE:     dependencies is described at:
 RULE:     https://github.com/canonical/ubuntu-mir/blob/main/vendoring/Rust.md
-RULE:   - An example of how Rust dependencies are vendored for gnome-snapshot
-RULE      can be found here:
-RULE      https://salsa.debian.org/ubuntu-dev-team/snapshot/-/blob/ubuntu/latest/debian/README.source
+RULE:   - Examples of how Rust dependencies can be vendored are
+RULE:     * authd:
+RULE:       https://github.com/ubuntu/authd/blob/main/debian/rules
+RULE:     * gnome-snapshot:
+RULE:       https://salsa.debian.org/ubuntu-dev-team/snapshot/-/blob/ubuntu/latest/debian/README.source
+RULE:     * s390-tools:
+RULE:       https://git.launchpad.net/ubuntu/+source/s390-tools/tree/debian/rules
 
 RULE: - All vendored dependencies (no matter what language) shall have a
 RULE:   way to be refreshed