Update unleash pkg version and sample code

Author: aliu39

docs/platforms/python/integrations/feature-flags/unleash.mdx

@@ -9,7 +9,7 @@ The [Unleash](https://www.getunleash.io/) integration tracks feature flag evalua
 
 ## Install
 
-Install `sentry-sdk` (>=2.19.3) and `UnleashClient` (>=6.0.1) from PyPI.
+Install `sentry-sdk` (>=2.20.0) and `UnleashClient` (>=6.0.1) from PyPI.
 
 ```bash
 pip install --upgrade sentry-sdk UnleashClient
@@ -39,20 +39,22 @@ Test the integration by evaluating a feature flag using your Unleash SDK before
 import sentry_sdk
 from UnleashClient import UnleashClient
 
-unleash_client = UnleashClient(...)  # See Unleash quickstart.
-test_flag_enabled = unleash_client.is_enabled("test-flag")
+unleash = UnleashClient(...)  # See Unleash quickstart.
+unleash.initialize_client()
 
+test_flag_enabled = unleash.is_enabled("test-flag")
 sentry_sdk.capture_exception(Exception("Something went wrong!"))
 ```
 
 ```python {tabTitle: Python, using get_variant}
 import sentry_sdk
 from UnleashClient import UnleashClient
 
-unleash_client = UnleashClient(...)  # See Unleash quickstart.
-test_flag_variant = unleash_client.get_variant("test-flag")
-test_flag_enabled = test_flag_variant["enabled"]
+unleash = UnleashClient(...)  # See Unleash quickstart.
+unleash.initialize_client()
 
+test_flag_variant = unleash.get_variant("test-flag")
+test_flag_enabled = test_flag_variant["enabled"]
 sentry_sdk.capture_exception(Exception("Something went wrong!"))
 ```