Update .gitlab-ci.yml

1 job for master in 22 seconds (queued for 1 second)
Name Stage Failure
failed
Test SSH Test
Use of uninitialized value $val in concatenation (.) or string at /usr/share/perl5/Debconf/Format/822.pm line 84, <GEN6> line 4.
Setting up libtcl8.6:amd64 (8.6.10+dfsg-1) ...
Setting up tcl8.6 (8.6.10+dfsg-1) ...
Setting up tcl-expect:amd64 (5.45.4-2build1) ...
Setting up expect (5.45.4-2build1) ...
Processing triggers for libc-bin (2.31-0ubuntu9.2) ...
$ echo "$SSH_PRIVATE_KEY" | base64 -d | tr -d '\r' | ssh-add - > /dev/null
Enter passphrase for (stdin):
Cleaning up file based variables
ERROR: Job failed: exit code 1