Prepare v0.15.0b1 release

Signed-off-by: Keith Battocchi <kebatt@microsoft.com>

Author: kbattocchi

README.md

@@ -51,10 +51,12 @@ For information on use cases and background material on causal inference and het
 
 # News
 
-**May 19, 2023:** Release v0.14.1, see release notes [here](https://github.com/py-why/EconML/releases/tag/v0.14.1)
+** November 11, 2023:** Release v0.15.0b1, see release notes [here](https://github.com/py-why/EconML/releases/tag/v0.15.0b1)
 
 <details><summary>Previous releases</summary>
 
+**May 19, 2023:** Release v0.14.1, see release notes [here](https://github.com/py-why/EconML/releases/tag/v0.14.1)
+
 **November 16, 2022:** Release v0.14.0, see release notes [here](https://github.com/py-why/EconML/releases/tag/v0.14.0)
 
 **June 17, 2022:** Release v0.13.1, see release notes [here](https://github.com/py-why/EconML/releases/tag/v0.13.1)

econml/_version.py

@@ -1,4 +1,4 @@
 # Copyright (c) PyWhy contributors. All rights reserved.
 # Licensed under the MIT License.
 
-__version__ = '0.14.1'
+__version__ = '0.15.0b1'