feat: automate nix package upgrades. Fixes #11691

[isubasinghe]

Fixes #11691

Motivation

The nix hash is extremely out of date and needs manual updating.

Modifications

A nix-hash task was added to the makefile that patches the nix flake.

Verification

Tested it by mutating the hash and running the nix-hash command.

Caution

This PR will likely result in someone needing to run make codegen on dependabot PRs relating to golang dependencies. I would be happy to do this.