Update URL of submodule 'viennagrid' to use HTTPS instead of SSH.
Update URL of submodule 'viennagrid' to use HTTPS instead of SSH.

If you check out using SSH but don't have an SSH key in your user's SSH configuration directory, GitHub rejects your request to clone the repository where the submodule is. If you use HTTPS instead, GitHub allows you to clone the repository without requiring an SSH key. This is useful if you don't have an SSH key set up or if you don't have a GitHub user account.

jonancm/viennagrid-python,jonancm/viennagrid-python,jonancm/viennagrid-python