Get the project to build successfully

[gabebw-grammarly]

This is a first commit before other work. It simply makes the package scripts (e.g. yarn build) work again.

This is split into a few commits:

• Always use this package's tsc, by using yarn tsc instead of just tsc

• Use Yarn v1.x. I picked this since we should specify a version and because 1.x likely matches the project's most recent configuration, but we can update it later in another PR.

• Fix build error about ts4.8 by specifying resolutions in package.json. We must resolve @types/node to a specific version because tslint (which is old) brings in a version of @types/node that does not work. We get these errors:

   node_modules/@types/node/ts4.8/test.d.ts:698:76 - error TS1005: ',' expected.
  698         target: F extends abstract new(...args: any) => any ? F : undefined;
                                                                                ~
  node_modules/@types/node/ts4.8/test.d.ts:702:22 - error TS1005: ',' expected.
  702         this: unknown;
  

  The long-term fix is to migrate from TSLint to ESLint and then use a more recent version of Typescript.