Upgrade to latest Zig, remove dependency on patched version of Zig (#96)

* Prepare to upgrade zig

* zig fmt

* AllocGate

* Update data_url.zig

* wip

* few files

* just headers now?

* I think everything works?

* Update mimalloc

* Update hash_map.zig

* Perf improvements to compensate for Allocgate

* Bump

* :camera:

* Update bun.lockb

* Less branching

* [js parser] Slightly reduce memory usage

* Update js_parser.zig

* WIP remove unused

* [JS parser] WIP support for `with` keyword

* Remove more dead code

* Fix all the build errors!

* cleanup

* Move `network_thread` up

* Bump peechy

* Update README.md