replace husky add in readme

[nemchik]

husky add is deprecated, use echo instead

I also included passing the --lockfile argument in the example as I believe it's the most desirable default behavior. The important thing to do there is adding the -- right before package-changed so that the --lockfile argument is passed to package-changed and not read by npx itself.

p.s. I accidentally created nemchik#5 months ago instead of creating it correctly here 😆

[nemchik]

@thdk I've restored my branch and reopened this so it can merge.

Separate note, I actually have interest in adding support for other package managers (pnpm and yarn) and I'm playing around in a dev branch in my repo to see how it goes. What I'm doing may end up feeling like a heavier rewrite because I'm also looking at updating some syntax, dependencies, and tooling. Even if it doesn't land it'll open the door for some discussion.