README: update CI badges, fix expected joint limits (#401)

Signed-off-by: Steve Peters <scpeters@openrobotics.org>

README.md

@@ -9,10 +9,10 @@
 
 Build | Status
 -- | --
-Test coverage | [![codecov](https://codecov.io/gh/gazebosim/gz-physics/branch/main/graph/badge.svg)](https://codecov.io/gh/gazebosim/gz-physics/branch/main)
-Ubuntu Focal | [![Build Status](https://build.osrfoundation.org/buildStatus/icon?job=ignition_physics-ci-main-focal-amd64)](https://build.osrfoundation.org/job/ignition_physics-ci-main-focal-amd64)
-Homebrew      | [![Build Status](https://build.osrfoundation.org/buildStatus/icon?job=ignition_physics-ci-main-homebrew-amd64)](https://build.osrfoundation.org/job/ignition_physics-ci-main-homebrew-amd64)
-Windows       | [![Build Status](https://build.osrfoundation.org/buildStatus/icon?job=ign_physics-ci-win)](https://build.osrfoundation.org/job/ign_physics-ci-win)
+Test coverage | [![codecov](https://codecov.io/gh/gazebosim/gz-physics/branch/gz-physics6/graph/badge.svg)](https://codecov.io/gh/gazebosim/gz-physics/branch/gz-physics6)
+Ubuntu Focal | [![Build Status](https://build.osrfoundation.org/buildStatus/icon?job=ignition_physics-ci-gz-physics6-focal-amd64)](https://build.osrfoundation.org/job/ignition_physics-ci-gz-physics6-focal-amd64)
+Homebrew      | [![Build Status](https://build.osrfoundation.org/buildStatus/icon?job=ignition_physics-ci-gz-physics6-homebrew-amd64)](https://build.osrfoundation.org/job/ignition_physics-ci-gz-physics6-homebrew-amd64)
+Windows       | [![Build Status](https://build.osrfoundation.org/buildStatus/icon?job=ign_physics-gz-6-win)](https://build.osrfoundation.org/job/ign_physics-gz-6-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.

dartsim/src/SDFFeatures_TEST.cc

@@ -344,12 +344,16 @@ TEST_P(SDFFeatures_TEST, CheckDartsimData)
   // Test that things were parsed correctly. These values are either stated or
   // implied in the test.world SDF file.
   verify(skeleton->getJoint(1)->getDof(0),
-         3.0, 0.0, 0.0, 0.0, -1e16, 1e16,
+         3.0, 0.0, 0.0, 0.0,
+         -std::numeric_limits<double>::infinity(),
+         std::numeric_limits<double>::infinity(),
          std::numeric_limits<double>::infinity(),
          std::numeric_limits<double>::infinity());
 
   verify(skeleton->getJoint(2)->getDof(0),
-         3.0, 0.0, 0.0, 0.0, -1e16, 1e16,
+         3.0, 0.0, 0.0, 0.0,
+         -std::numeric_limits<double>::infinity(),
+         std::numeric_limits<double>::infinity(),
          std::numeric_limits<double>::infinity(),
          std::numeric_limits<double>::infinity());