Bump actions/upload-artifact from 5.0.0 to 6.0.0 (#1067)

Bumps [actions/upload-artifact](https://github.com/actions/upload-artifact) from 5.0.0 to 6.0.0.
- [Release notes](https://github.com/actions/upload-artifact/releases)
- [Commits](actions/upload-artifact@330a01c...b7c566a)

---
updated-dependencies:
- dependency-name: actions/upload-artifact
  dependency-version: 6.0.0
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

.github/workflows/deploy-backend.yml

@@ -83,7 +83,7 @@ jobs:
         run: make plan-ci
 
       - name: Save Terraform Plan
-        uses: actions/upload-artifact@330a01c490aca151604b8cf639adc76d48f6c5d4
+        uses: actions/upload-artifact@b7c566a772e6b6bfb58ed0dc250532a479d7789f
         with:
           name: ${{ env.ENVIRONMENT }}-${{ env.SUB_ENVIRONMENT }}-tfplan
           path: infrastructure/instance/tfplan