[Gitlab] how to edit gitlab-runner tags

Simply go to CI / CD > runner on Gitlab website, focus on your needed runner, press on modify icon and at the opened page modify runner tags.

It shouldn't be done from runner's machine, only at Gitlab.

[gitlab] multiline environment variable passed as empty line fix

Use correct way to pass variable in your .gitlab-ci.yml in `script` section:

- echo "$PROD_PRIVATE_KEY" > config/nginx/certs/site.dev.priv

Then be sure you disabled "protected" option for your variable in Gitlab Settings > CI / CD.