Update Dockerfile

[meztez]

for stringi, pak will install icu-dev if not found

[gaborcsardi]

So the update is not needed? That's why you closed it?

[meztez]

its icu-libs for stringi, i'm spending the weekend migrating all the wordload over to alpine on aws.

Anything that will depend on stringi will install icu-dev if not specified. stringi stopped shipping its own icu subset last year from what I read.

[gaborcsardi]

Yes, we could probably turn off the automatic system dependency installation on r-minimal until pak knows about run-time and build-time dependencies.