feat(#263): replace istanbuljs to galatajs

[9ssi7]

Checklist

• [x] run npm run test and npm run benchmark
• [x] tests and/or benchmarks are included
• [x] documentation is changed or added
• [x] commit message and code follows the Developer's Certification of Origin and the Code of conduct

I had a PR for the istanbuljs framework I developed yesterday and then got a feedback that the name istanbuljs was confusing. It was confusing when you think about it. I renamed the package name to galatajs.

fixed #263