Update googletest to 1.13

Fix issue with CMake 4.0

test/googletest-1.13.0/googlemock/README.md

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+# Googletest Mocking (gMock) Framework
+
+### Overview
+
+Google's framework for writing and using C++ mock classes. It can help you
+derive better designs of your system and write better tests.
+
+It is inspired by:
+
+*   [jMock](http://www.jmock.org/)
+*   [EasyMock](http://www.easymock.org/)
+*   [Hamcrest](http://code.google.com/p/hamcrest/)
+
+It is designed with C++'s specifics in mind.
+
+gMock:
+
+-   Provides a declarative syntax for defining mocks.
+-   Can define partial (hybrid) mocks, which are a cross of real and mock
+    objects.
+-   Handles functions of arbitrary types and overloaded functions.
+-   Comes with a rich set of matchers for validating function arguments.
+-   Uses an intuitive syntax for controlling the behavior of a mock.
+-   Does automatic verification of expectations (no record-and-replay needed).
+-   Allows arbitrary (partial) ordering constraints on function calls to be
+    expressed.
+-   Lets a user extend it by defining new matchers and actions.
+-   Does not use exceptions.
+-   Is easy to learn and use.
+
+Details and examples can be found here:
+
+*   [gMock for Dummies](https://google.github.io/googletest/gmock_for_dummies.html)
+*   [Legacy gMock FAQ](https://google.github.io/googletest/gmock_faq.html)
+*   [gMock Cookbook](https://google.github.io/googletest/gmock_cook_book.html)
+*   [gMock Cheat Sheet](https://google.github.io/googletest/gmock_cheat_sheet.html)
+
+GoogleMock is a part of
+[GoogleTest C++ testing framework](http://github.com/google/googletest/) and a
+subject to the same requirements.