fix: `example/build_file_generation/README.md` (#1164)

This PR updates outdated README.md of example.

Closes #1160

---------

Signed-off-by: Thulio Ferraz Assis <3149049+f0rmiga@users.noreply.github.com>
Co-authored-by: Thulio Ferraz Assis <3149049+f0rmiga@users.noreply.github.com>

examples/build_file_generation/README.md

diff --git a/examples/build_file_generation/README.md b/examples/build_file_generation/README.md
index 9b2fe1a..cd3cd1f 100644
--- a/examples/build_file_generation/README.md
+++ b/examples/build_file_generation/README.md
@@ -5,7 +5,9 @@
 automatically created just by running
 
 ```sh
-$ bazel run //:gazelle
+bazel run //:requirements.update
+bazel run //:gazelle_python_manifest.update
+bazel run //:gazelle
 ```
 
 As a demo, try creating a `__main__.py` file in this directory, then