update readme badge

Signed-off-by: Ian Chen <ichen@openrobotics.org>

Author: iche033

README.md

@@ -9,10 +9,10 @@
 
 Build | Status
 -- | --
-Test coverage | [![codecov](https://codecov.io/gh/gazebosim/gz-physics/tree/gz-physics8/graph/badge.svg)](https://codecov.io/gh/gazebosim/gz-physics/tree/gz-physics8)
-Ubuntu Noble  | [![Build Status](https://build.osrfoundation.org/buildStatus/icon?job=gz_physics-ci-gz-physics8-noble-amd64)](https://build.osrfoundation.org/job/gz_physics-ci-gz-physics8-noble-amd64)
-Homebrew      | [![Build Status](https://build.osrfoundation.org/buildStatus/icon?job=gz_physics-ci-gz-physics8-homebrew-amd64)](https://build.osrfoundation.org/job/gz_physics-ci-gz-physics8-homebrew-amd64)
-Windows       | [![Build Status](https://build.osrfoundation.org/buildStatus/icon?job=gz_physics-8-win)](https://build.osrfoundation.org/job/gz_physics-8-win)
+Test coverage | [![codecov](https://codecov.io/gh/gazebosim/gz-physics/tree/main/graph/badge.svg)](https://codecov.io/gh/gazebosim/gz-physics/tree/main)
+Ubuntu Noble  | [![Build Status](https://build.osrfoundation.org/buildStatus/icon?job=gz_physics-ci-main-noble-amd64)](https://build.osrfoundation.org/job/gz_physics-ci-main-noble-amd64)
+Homebrew      | [![Build Status](https://build.osrfoundation.org/buildStatus/icon?job=gz_physics-ci-main-homebrew-amd64)](https://build.osrfoundation.org/job/gz_physics-ci-main-homebrew-amd64)
+Windows       | [![Build Status](https://build.osrfoundation.org/buildStatus/icon?job=gz_physics-main-win)](https://build.osrfoundation.org/job/gz_physics-main-win)
 
 Gazebo Physics, a component of [Gazebo](https://gazebosim.org), provides an abstract physics interface
 designed to support simulation and rapid development of robot applications.