Can't install cashscript on bundlephobia

[rkalis]

When trying to check cashscript's bundle size on bundlephobia, we run into an error.

[mr-zwets]

we should re-try after a fix for #224 to see whether they are related

[mr-zwets]

we still get a build error, from the 'Terser' minfier

Unexpected token: name (Promise) [main.bundle.js:4838,184]