Bump DeterminateSystems/flakehub-push from 5 to 7

Bumps [DeterminateSystems/flakehub-push](https://github.com/determinatesystems/flakehub-push) from 5 to 7.
- [Release notes](https://github.com/determinatesystems/flakehub-push/releases)
- [Commits](DeterminateSystems/flakehub-push@v5...v7)

---
updated-dependencies:
- dependency-name: DeterminateSystems/flakehub-push
  dependency-version: '7'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

.github/workflows/flakehub-publish.yaml

@@ -12,7 +12,7 @@ jobs:
     steps:
       - uses: 'actions/checkout@v4'
       - uses: 'DeterminateSystems/nix-installer-action@v16'
-      - uses: 'DeterminateSystems/flakehub-push@v5'
+      - uses: 'DeterminateSystems/flakehub-push@v7'
         with:
           name: 'VijayakumarRavi/vjvim'
           rolling: true