Fix issue in cloning app templates repo in windows

[hawflau]

Which issue(s) does this change fix?

#3946

Why is this change necessary?

App templates repo contains some very long paths in which Windows doesn't support them as it has a limitation of 260 chars.

How does it address the issue?

This change modifies the git clone command by appending --config core.longpaths=true if the system is Windows. The config is only applied for the cloned repo (i.e. the app templates repo) and won't affect user's system settings.

What side effects does this change have?

No

Mandatory Checklist

PRs will only be reviewed after checklist is complete

• Add input/output type hints to new functions/methods
• Write design document if needed (Do I need to write a design document?)
• Write/update unit tests
• Write/update integration tests
• Write/update functional tests if needed
• make pr passes
• make update-reproducible-reqs if dependencies were changed
• Write documentation

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.