feat: add httpx 0.28 testing for Python 3.14

Verified httpx 0.28.1 API compatibility: _client.Client.send,
_client.AsyncClient.send, USE_CLIENT_DEFAULT all exist with
same signatures. url.netloc remains bytes type.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: wu-sheng

docs/en/setup/Plugins.md

@@ -30,7 +30,7 @@ or a limitation of SkyWalking auto-instrumentation (welcome to contribute!)
 | [happybase](https://happybase.readthedocs.io) | Python >=3.12 - ['1.3.0']; Python >=3.10 - ['1.2.0'];  | `sw_happybase` |
 | [http_server](https://docs.python.org/3/library/http.server.html) | Python >=3.7 - ['*'];  | `sw_http_server` |
 | [werkzeug](https://werkzeug.palletsprojects.com/) | Python >=3.7 - ['1.0.1', '2.0'];  | `sw_http_server` |
-| [httpx](https://www.python-httpx.org/) | Python >=3.13 - ['0.23.*']; Python >=3.10 - ['0.23.*', '0.22.*'];  | `sw_httpx` |
+| [httpx](https://www.python-httpx.org/) | Python >=3.14 - ['0.28.*', '0.23.*']; Python >=3.13 - ['0.23.*']; Python >=3.10 - ['0.23.*', '0.22.*'];  | `sw_httpx` |
 | [kafka-python](https://kafka-python.readthedocs.io) | Python >=3.12 - ['2.3']; Python >=3.10 - ['2.0'];  | `sw_kafka` |
 | [loguru](https://pypi.org/project/loguru/) | Python >=3.7 - ['0.6.0', '0.7.0'];  | `sw_loguru` |
 | [mysqlclient](https://mysqlclient.readthedocs.io/) | Python >=3.7 - ['2.1.*'];  | `sw_mysqlclient` |

skywalking/plugins/sw_httpx.py

@@ -23,6 +23,7 @@
 link_vector = ['https://www.python-httpx.org/']
 support_matrix = {
     'httpx': {
+        '>=3.14': ['0.28.*', '0.23.*'],
         '>=3.13': ['0.23.*'],
         '>=3.10': ['0.23.*', '0.22.*'],
     }