Bump propshaft from 1.2.1 to 1.3.1 (rubyforgood#648)

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>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Polly Schandorf <pollygee@users.noreply.github.com>

Author: dependabot[bot]

Gemfile.lock

@@ -241,7 +241,7 @@ GEM
       prettyprint
     prettyprint (0.2.0)
     prism (1.5.1)
-    propshaft (1.2.1)
+    propshaft (1.3.1)
       actionpack (>= 7.0.0)
       activesupport (>= 7.0.0)
       rack