Crashing on invalid JSON

Error:

```
SyntaxError: Unexpected end of JSON input
    at Cache.parse (<anonymous>)
    at Cache.get (file:///home/ubuntu/iobio-backend-services/pheno/node_modules/flache/index.js:29:24)
    at async handlePhenolyzer (file:///home/ubuntu/iobio-backend-services/pheno/index.js:56:17)
```