NO-ISSUE: Set locale to "en-US" before generating image-builder and run-script-if READMEs

[ljmotta]

Adding this prevent yargs of using the machine locale.

[tiagobento]

What problem does this solve? I get that this pins the locale, but why do we need that?

[ljmotta]

@tiagobento yargs --help is used to write the the image-builder and run-script-if README files. By default yargs use the machine locale, so in my case it was en-BR, which re-writed the files using Portuguese.

[tiagobento]

Maybe instead of hardcoding it to all the invocations of image-builder and run-script-if, we could simply foce the locale in the invocations specific to building the READMEs, no?

[tiagobento]

I mean, defining a locale is pretty out of scope for run-script-if and image-builder.