Fix npmignore and update build script

Signed-off-by: Snorre Magnus Davøen <snorre.davoen@nsd.uib.no>
2 jobs for v3.0.0-alpha.2 in 31 seconds
latest
Status Job ID Name Coverage
  Test
passed #8774
test-release

00:00:19

 
  Publish
passed #8775
publish

00:00:11