Add riscv64 to binary releases

Describe the feature you'd like Id like to have cloudflared compiled as a binary I can install for debian 13, since I run a riscv64 system, not having to compile every release would be somewhat convient

Describe alternatives you've considered manual compiling program and systemd daemon I wrote

Additional context nothing much, other than perhaps adding riscv64 would be wise as maybe more riscv64 based servers might exiest in the future idk