Rename ownership to maintainers as friendlier phrasing.

Followup to suggestion in
#489

PiperOrigin-RevId: 324681886

Author: alanchiao

README.md

@@ -30,12 +30,12 @@ By participating, you are expected to uphold this code.**
 [GitHub issues](https://github.com/tensorflow/model-optimization/issues) for
 tracking requests and bugs.**
 
-## Ownership
+## Maintainers
 
 <table>
   <tr>
     <th>Subpackage</th>
-    <th>Owners</th>
+    <th>Maintainers</th>
   </tr>
   <tr>
     <td>tfmot.clustering</td>

tensorflow_model_optimization/g3doc/guide/clustering/index.md

@@ -1,6 +1,6 @@
 # Weight clustering
 
-<sub>Owned by Arm ML Tooling</sub>
+<sub>Maintained by Arm ML Tooling</sub>
 
 This document provides an overview on weight clustering to help you determine how it fits with your use case.
 

tensorflow_model_optimization/g3doc/guide/pruning/index.md

@@ -1,6 +1,6 @@
 # Trim insignificant weights
 
-<sub>Owned by TensorFlow Model Optimization</sub>
+<sub>Maintained by TensorFlow Model Optimization</sub>
 
 This document provides an overview on model pruning to help you determine how it
 fits with your use case.

tensorflow_model_optimization/g3doc/guide/quantization/training.md

@@ -1,6 +1,6 @@
 # Quantization aware training
 
-<sub>Owned by TensorFlow Model Optimization</sub>
+<sub>Maintained by TensorFlow Model Optimization</sub>
 
 There are two forms of quantization: post-training quantization and
 quantization aware training. Start with [post-training quantization](post_training.md)