Bump propshaft from 1.2.1 to 1.3.1

Bumps [propshaft](https://github.com/rails/propshaft) from 1.2.1 to 1.3.1.
- [Release notes](https://github.com/rails/propshaft/releases)
- [Commits](rails/propshaft@v1.2.1...v1.3.1)

---
updated-dependencies:
- dependency-name: propshaft
  dependency-version: 1.3.1
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]