Added rustfmt to gitlab ci

1 job for <span class="ref-name">part-3</span> in 3 minutes and 4 seconds (queued for 1 second)
Status Job ID Name Coverage
  Test
failed #46965296
test:cargo

00:03:04

 
Name Stage Failure
failed
test:cargo Test There is an unknown failure, please try again
Using docker image scorpil/rust:stable ID=sha256:2329dc35385be0fc3b533197279071565687a8e5555ff9ed25209d957502651e for build container...
Running on runner-72989761-project-1551015-concurrent-0 via runner-72989761-srm-1515277748-e029b8b9...
Cloning repository...
Cloning into '/builds/arthurc/rustn64'...
Checking out 6a1d8278 as part-3...
Skipping Git submodules setup
$ rustup install nightly
/bin/bash: line 54: rustup: command not found
ERROR: Job failed: exit code 1