chore: Bump meltano in /.github/workflows in the ci group

Bumps the ci group in /.github/workflows with 1 update: [meltano](https://github.com/meltano/meltano).


Updates `meltano` from 3.7.7 to 3.7.8
- [Release notes](https://github.com/meltano/meltano/releases)
- [Changelog](https://github.com/meltano/meltano/blob/main/CHANGELOG.md)
- [Commits](meltano/meltano@v3.7.7...v3.7.8)

---
updated-dependencies:
- dependency-name: meltano
  dependency-version: 3.7.8
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: ci
...

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

Author: dependabot[bot]

.github/workflows/constraints.txt

@@ -1,3 +1,3 @@
-meltano==3.7.7
+meltano==3.7.8
 tox==4.26.0
 tox-uv==1.26.0