Modifications to Issues Template

[Ankith-Cirgir]

Change dates from 2025 to 2026 on issues template

[Ankith-Cirgir]

On Eunice Request, Made minor changes on issues template:
"We are very excited to meet you at BrainHack Vanderbilt 2025 🎉." and "first register for BrainHack Vanderbilt 2025"
To
"We are very excited to meet you at BrainHack Vanderbilt 2026 🎉." and "first register for BrainHack Vanderbilt 2026"