Update miden.md - reordered sequence of milestones

[stratisnik]

Reordered the sequence of the milestones as recommended by Vechain1, miden-5.md (PR #248)

Grant Application Checklist

• [ Y] The applications/application-template.md or applications/research-template.md has been copied, renamed ( "project_name.md") and updated.
• [ Y] An Ethereum address for the payment of the milestones is provided inside the application.
• [ Y] The total funding amount of the project is up to USD $30k for every grant applications.
• [ Y] The initial PR contains only one commit (squash if needed before submitting your PR).

[stratisnik]

@NecoSherry sequence of milestones updated here for the release of funds.

[stratisnik]

@NecoSherry adjusted as requested