Fixes value assignment of terms in the termination manager (#488)

# Description

This MR fixes a regression introduced in 0.15.1. The term values were
assigned using an OR operator. However, since they were never being
cleared, the values were incorrect.

## Type of change

- Bug fix (non-breaking change which fixes an issue)

## Checklist

- [x] I have run the [`pre-commit` checks](https://pre-commit.com/) with
`./orbit.sh --format`
- [x] I have made corresponding changes to the documentation
- [x] My changes generate no new warnings
- [ ] I have added tests that prove my fix is effective or that my
feature works
- [x] I have run all the tests with `./orbit.sh --test` and they pass
- [x] I have updated the changelog and the corresponding version in the
extension's `config/extension.toml` file
- [x] I have added my name to the `CONTRIBUTORS.md` or my name already
exists there

source/extensions/omni.isaac.orbit/config/extension.toml

 [package]
 
 # Note: Semantic Versioning is used: https://semver.org/
-version = "0.15.8"
+version = "0.15.9"
 
 # Description
 title = "ORBIT framework for Robot Learning"

source/extensions/omni.isaac.orbit/docs/CHANGELOG.rst

 Changelog
 ---------
 
+0.15.9 (2024-04-04)
+~~~~~~~~~~~~~~~~~~~
+
+Fixed
+^^^^^
+
+* Fixed assignment of individual termination terms inside the :class:`omni.isaac.orbit.managers.TerminationManager`
+  class. Earlier, the terms were being assigned their values through an OR operation which resulted in incorrect
+  values. This regression was introduced in version 0.15.1.
+
+
 0.15.8 (2024-04-02)
 ~~~~~~~~~~~~~~~~~~~
 
 Added
 ^^^^^
-* Adds option to define ordering of points for the mesh-grid generation in the
+
+* Added option to define ordering of points for the mesh-grid generation in the
   :func:`omni.isaac.orbit.sensors.ray_caster.patterns.grid_pattern`. This parameter defaults to 'xy'
   for backward compatibility.
 
@@ -62,7 +74,8 @@ Added
 Fixed
 ^^^^^
 
-* Fixed the NonHolonomicActionCfg variable naming from joint_vel to _joint_vel_command to match the initialized variable in the init() function.
+* Fixed the :class:`omni.isaac.orbit.envs.mdp.actions.NonHolonomicActionCfg` class to use
+  the correct variable when applying actions.
 
 
 0.15.3 (2024-03-21)

source/extensions/omni.isaac.orbit/omni/isaac/orbit/managers/termination_manager.py

@@ -163,7 +163,7 @@ class TerminationManager(ManagerBase):
             else:
                 self._terminated_buf |= value
             # add to episode dones
-            self._term_dones[name] |= value
+            self._term_dones[name][:] = value
         # return combined termination signal
         return self._truncated_buf | self._terminated_buf