[PhpUnitBridge] Add strtotime() to ClockMock

Author: alamirault

components/phpunit_bridge.rst

@@ -566,9 +566,13 @@ Clock Mocking
 
 The :class:`Symfony\\Bridge\\PhpUnit\\ClockMock` class provided by this bridge
 allows you to mock the PHP's built-in time functions ``time()``, ``microtime()``,
-``sleep()``, ``usleep()``, ``gmdate()``, and ``hrtime()``. Additionally the
-function ``date()`` is mocked so it uses the mocked time if no timestamp is
-specified.
+``sleep()``, ``usleep()``, ``gmdate()``, ``hrtime()``, and ``strtotime()``.
+Additionally the function ``date()`` is mocked so it uses the mocked time if no
+timestamp is specified.
+
+.. versionadded:: 7.4
+
+    Support for mocking the ``strtotime()`` function was introduced in Symfony 7.4.
 
 Other functions with an optional timestamp parameter that defaults to ``time()``
 will still use the system time instead of the mocked time. This means that you