fix: quote sysctl keys in config.toml template, so that the TOML is properly parsed by gitlab-runner

[gwarf]

Due to the fact that the sysctl keys contain periods, like net.ipv4.ip_forward, we need to quote them, so that the TOML is properly parsed by gitlab-runner, like when using gitlab-runner verify.

Parsing error from gitlab-runner verify:

root@vps-0a441234:/home/ubuntu# gitlab-runner verify
Runtime platform                                    arch=amd64 os=linux pid=557091 revision=139a0ac0 version=18.4.0
Running in system-mode.

FATAL: decoding configuration file: toml: (last key "runners.docker.sysctls.net"): incompatible types: TOML value has type map[string]any; destination has type string

See also example at https://docs.gitlab.com/runner/configuration/advanced-configuration/

This is onlly relevant to configuration done via the template as per #400.

[guenhter]

@LoniasGR As you started bring in this new feature, are you willing to also do some reviews?

[LoniasGR]

Sure, I can take a look in the next few days

[LoniasGR]

Hi, first of all, although not from this PR, line 127 needs to be changed to

{% if gitlab_runner.extra_configs is defined %}

otherwise it fails if extra_configs does not exist.

[gwarf]

Hi, first of all, although not from this PR, line 127 needs to be changed to

{% if gitlab_runner.extra_configs is defined %}

otherwise it fails if extra_configs does not exist.

Thanks, I fixed the test.

[guenhter]

@LoniasGR just from a process pov: when you are happy with this, approve it. When it is approved I'll merge it.

[LoniasGR]

LGTM