Update dagger-io requirement from ~=0.9.7 to ~=0.15.0

Updates the requirements on [dagger-io](https://github.com/dagger/dagger) to permit the latest version.
- [Release notes](https://github.com/dagger/dagger/releases)
- [Changelog](https://github.com/dagger/dagger/blob/main/CHANGELOG.md)
- [Commits](dagger/dagger@v0.9.7...v0.15.0)

---
updated-dependencies:
- dependency-name: dagger-io
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

dagger/requirements.txt

@@ -1,3 +1,3 @@
 beartype<0.18.0
-dagger-io~=0.9.7
+dagger-io~=0.15.0
 python-dotenv