build(deps): bump peter-evans/create-pull-request from 5 to 6

Bumps [peter-evans/create-pull-request](https://github.com/peter-evans/create-pull-request) from 5 to 6.
- [Release notes](https://github.com/peter-evans/create-pull-request/releases)
- [Commits](peter-evans/create-pull-request@v5...v6)

---
updated-dependencies:
- dependency-name: peter-evans/create-pull-request
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

.github/workflows/update.yml

@@ -17,7 +17,7 @@ jobs:
             access-tokens = github.com=${{ github.token }}
       - uses: jessestricker/nix-flake-update@v1
         id: nix-update
-      - uses: peter-evans/create-pull-request@v5
+      - uses: peter-evans/create-pull-request@v6
         with:
           branch: nix-update
           commit-message: "build(nix): update flake lock"