Update readme with text for installing on m1 macs

[brian-penguin]

No description provided.

[joshuaclayton]

@brimatteng I'm wondering if we should instead default to the Rust allocator and have people opt-in. That way, OOTB it'll work both on Intel and Apple Silicon. The perf bump is nice, but on the majority of projects should be sub-5s on new-ish hardware anyways. What do you think?

[brian-penguin]

It's probably better to pass a flag and have it "work" by default, I didn't notice that much real difference in build time between the two branches

[joshuaclayton]

@brimatteng I've attempted to address this indirectly by updating our Homebrew formula to opt-in to MiMalloc here.

[joshuaclayton]

@brimatteng I've merged the update to our Homebrew formula, so the stock brew install complexity should now work regardless of architecture.

I'm thinking that we can close this without merging, but will leave that to you to confirm. Thanks for flagging!

[brian-penguin]

I'm good with closing it. Thanks for updating