Fix warning on lint for cffstr.jest.spec.ts

[abelsiqueira]

After #630, there are no more single quotes inside double quotes, so the linter complains that the string should have single quotes:

/tmp/cff-initializer-javascript/test/jest/__tests__/store/cffstr.jest.spec.ts
  26:44  warning  Strings must use singlequote  quotes

Just changing from double to single quotes in that line should fix it.

[abelsiqueira]

Done in #646

[fdiblen]

Can we close this?

[abelsiqueira]

Yes