feat(build): add dual CJS+ESM build and TypeScript declarations#442

lukeundtrug wants to merge 1 commit intosourcegraph:mainsourcegraph/scip-typescript:mainfrom

lukeundtrug:feature/make-useable-as-a-librarylukeundtrug/scip-typescript:feature/make-useable-as-a-libraryCopy head branch name to clipboard