Set GOARM64=v8.4,lse,crypto

Add support for GOARM64 environment variable in cloudflared builds to optimize performance on modern ARM servers, particularly AWS Graviton processors. This would allow users to target specific ARM CPU features and extensions like LSE (Large System Extensions) and hardware crypto acceleration.

- Enables optimal performance on ARM servers by utilizing hardware-specific features
Reduces CPU usage through hardware-accelerated crypto operations
- Improves multi-threaded performance with LSE atomic instructions
- Allows fine-grained control over ARM architecture compatibility requirements

I propose setting `GOARM64=v8.4,lse,crypto`

This provides:

- ARMv8.4-A features for improved virtualization and memory management
- LSE for better atomic operations and concurrency
- Hardware crypto acceleration for TLS operations

This setting would provide optimal performance while maintaining compatibility with:

- AWS Graviton 2/3
- Modern ARM servers like Ampere Altra
- Other ARMv8.4+ processors