build(deps-dev): bump singer-sdk[testing] from 0.44.2 to 0.48.1

Bumps [singer-sdk[testing]](https://github.com/meltano/sdk) from 0.44.2 to 0.48.1.
- [Release notes](https://github.com/meltano/sdk/releases)
- [Changelog](https://github.com/meltano/sdk/blob/main/CHANGELOG.md)
- [Commits](meltano/sdk@v0.44.2...v0.48.1)

---
updated-dependencies:
- dependency-name: singer-sdk[testing]
  dependency-version: 0.48.1
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

pyproject.toml

@@ -21,7 +21,7 @@ license = "Apache-2.0"
 license-files = [ "LICENSE" ]
 requires-python = "<3.13,>=3.9"
 dependencies = [
-    "singer-sdk==0.44.2",
+    "singer-sdk==0.48.1",
 ]
 
 [project.optional-dependencies]