Upgrade to Alpine 3.9

[mastersingh24]

Alpine 3.9 is now available. Suggest updating Node 10 image to Alpine 3.9

[LaurentGoderre]

Duplicate of #990

[drwoods]

I see that the 10.15.3 image is using Alpine 3.9.
Will the Node 8 image be updated to 3.9 on the next release?

[LaurentGoderre]

Assuming the next release to version 8 isn't a security update, yes.

[tvainika]

Fixed in a8dbfa5 on 2019-04-16