Update example/share-services/northwind/flake.lock (#521)

Automated changes by the
[update-flake-lock](https://github.com/DeterminateSystems/update-flake-lock)
GitHub Action.

```
Flake lock file updates:

• Updated input 'nixpkgs':
    'github:nixos/nixpkgs/12a55407652e04dcf2309436eb06fef0d3713ef3?narHash=sha256-N4cp0asTsJCnRMFZ/k19V9akkxb7J/opG%2BK%2BjU57JGc%3D' (2025-05-16)
  → 'github:nixos/nixpkgs/59138c7667b7970d205d6a05a8bfa2d78caa3643?narHash=sha256-7gGa49iB9nCnFk4h/g9zwjlQAyjtpgcFkODjcOQS0Es%3D' (2025-05-31)
• Updated input 'services-flake':
    'github:juspay/services-flake/6330e87c2079313442963eeb9012ee05daeea880?narHash=sha256-xTvSq5C%2BTBvnlko1W4to2HkEsvGTR4yLq9%2BVHL6glm0%3D' (2025-05-16)
  → 'github:juspay/services-flake/ebb2ef66e4f582c7bea2f8baeec1136e36a26747?narHash=sha256-oeht0LloBLyVdb0vF%2BOSD2IJAuy1abGJO/MngldqpmM%3D' (2025-05-30)
```

Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>
Co-authored-by: Shivaraj B H <me@shivaraj-bh.in>

Author: 3 people