Fix somme encoding issues in Dockerfile

2 jobs for master in 22 minutes and 48 seconds (queued for 1 second)
Status Job ID Name Coverage
  Test
failed #59475
lint:2.7

00:11:08

failed #59474
lint:3

00:11:40

 
Name Stage Failure
failed
lint:3 Test There is an unknown failure, please try again
No job trace
failed
lint:2.7 Test There is an unknown failure, please try again
No job trace