Bump golang.org/x/mod from 0.14.0 to 0.15.0 (#300)

Bumps [golang.org/x/mod](https://github.com/golang/mod) from 0.14.0 to 0.15.0.
- [Commits](golang/mod@v0.14.0...v0.15.0)

---
updated-dependencies:
- dependency-name: golang.org/x/mod
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]