openvdb_vendor in backlist for RHEL 8 (#305)

Signed-off-by: Steve Macenski <[email protected]>

humble/release-rhel-build.yaml

@@ -34,6 +34,7 @@ package_blacklist:
 - octovis  # Build failures on RHEL
 - open3d_conversions  # open3d has no RPM package for RHEL
 - openni2_camera  # libopenni2-dev does not exist on RHEL
+- openvdb_vendor  # g++ version too old on RHEL for OpenVDB
 - ouster_msgs  # libtins-dev has no RPM package for RHEL
 - pepper_meshes  # Missing license agreement patches for packaging https://github.com/ros-naoqi/pepper_meshes2-release/issues/1
 - popf  # COIN-OR packages have no RPM packages for RHEL 8