Bump ruff linter target to Python 3.14.

This solves a bunch of really weird complaints about class methods:
```
ERROR Expected a callable, got `classmethod[Unknown, [**kwargs: Any], Any]` [not-callable]
  --> fastly_compute/tests/test_exception_remapping.py:82:13
   |
82 |             self.raise_int_by_surprise()
```

Author: erikrose

fastly_compute/log.py

@@ -71,7 +71,7 @@ def __init__(self, endpoint: wit_log.Endpoint):
             OpenError.RESERVED: LogEndpointInvalidNameError,
         }
     )
-    def open(cls, name: str) -> "LogEndpoint":
+    def open(cls, name: str) -> Self:
         r"""Open a logging endpoint by name.
 
         Names are case sensitive. Calling open() with a name that doesn't

fastly_compute/requests/timeout.py

@@ -4,7 +4,7 @@
 requests-compatible timeouts and Fastly-specific granular timeout controls.
 """
 
-from typing import override
+from typing import Self, override
 
 
 class TimeoutConfig:
@@ -54,7 +54,7 @@ def between_bytes_ms(self) -> int:
     @classmethod
     def from_requests_timeout(
         cls, timeout: None | float | tuple[float, float]
-    ) -> "TimeoutConfig":
+    ) -> Self:
         """Create TimeoutConfig from requests-compatible timeout parameter.
 
         Args:

pyproject.toml

@@ -37,7 +37,7 @@ addopts = [
 ]
 
 [tool.ruff]
-target-version = "py312"
+target-version = "py314"
 line-length = 88
 
 [tool.ruff.lint]