fix(scanner/suse): skip table header in zypper -q lu

[MaineK00n]

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What did you implement:

The current method of skipping table headers in the output of zypper -q lu does not work when spaces are added.
So, until we read a line consisting only of -+, we assume it is a table header.

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?

a2c6f9dcb28a:~ # zypper -q lu
S  | Repository                                                   | Name     | Current Version | Available Version | Arch
---+--------------------------------------------------------------+----------+-----------------+-------------------+-------
v  | Update repository with updates from SUSE Linux Enterprise 15 | iproute2 | 5.14-150400.1.8 | 6.4-150600.7.3.1  | x86_64

before

$ vuls scan -debug
...
[Dec 18 20:36:05] DEBUG [docker] Executing... zypper -q --no-color lu
[Dec 18 20:36:07] DEBUG [docker] execResult: servername: docker
  cmd: /usr/bin/ssh -o StrictHostKeyChecking=yes -o LogLevel=quiet -o ConnectionAttempts=3 -o ConnectTimeout=10 -o ControlMaster=auto -o ControlPath=/home/mainek00n/.vuls/cm-a3722a6d-%C -o Controlpersist=10m -l root -p 2222 -i /home/mainek00n/github/github.com/MaineK00n/vuls-targets-docker/.ssh/id_rsa -o PasswordAuthentication=no 127.0.0.1
  exitstatus: 0
  stdout: S  | Repository                                                   | Name     | Current Version | Available Version | Arch
---+--------------------------------------------------------------+----------+-----------------+-------------------+-------
v  | Update repository with updates from SUSE Linux Enterprise 15 | iproute2 | 5.14-150400.1.8 | 6.4-150600.7.3.1  | x86_64

  stderr: stty: 'standard input': Inappropriate ioctl for device

  err: %!s(<nil>)
[Dec 18 20:36:07] DEBUG [localhost] Panic: runtime error: index out of range [1] with length 1 on docker

after

$ vuls scan -debug
...
Scan Summary
================
docker	opensuse.leap15.6	148 installed, 1 updatable

Checklist:

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• Write tests
• Write documentation
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Is this ready for review?: YES

Reference

[shino]

🎉