Fix security vulnerability

[connectdotz]

in order to address security vulnerability, upgraded most dependencies except the following:

• flow-bin: the newer version caused tons of errors that didn't seem to be trivial to fix. Giving we do plan to move to typescript, decided not to invest too much time here, so left it unchanged.
• danger: it has a dependency (set-value) that is flagged as a high-severity issue, and there is no fix from danger yet. So removing it for now and we can revisit it during github actions migration.

The upgrade of jest-snapshot brought in a breaking change that buildSnapshotResolver has become an async call. Therefore made some change in Snapshot.js.

Also fixed some eslint error and config due to upgrade.