docs: add gitlab-ci section to troubleshooting (puppeteer#8664)

Adding explanatory section with detailed manual on how to launch puppeteer on GitlabCI

docs/troubleshooting.md

@@ -359,6 +359,31 @@ USER pptruser
 ...
 ```
 
+## Running Puppeteer on GitlabCI
+
+This is very similar to some of the instructions above, but require a bit different configuration to finally achieve success.
+
+Usually the issue looks like this:
+
+```bash
+Error: Failed to launch chrome! spawn /usr/bin/chromium-browser ENOENT
+```
+
+You need to patch two places:
+
+1. Your `gitlab-ci.yml` config
+2. Arguments' list when launching pupepeteer
+
+In `gitlab-ci.yml` we need to install some packages to make it possible to launch headless Chrome in your docker env:
+
+```yml
+before_script:
+  - apt-get update
+  - apt-get install -yq gconf-service libasound2 libatk1.0-0 libc6 libcairo2 libcups2 libdbus-1-3 libexpat1 libfontconfig1 libgcc1 libgconf-2-4 libgdk-pixbuf2.0-0 libglib2.0-0 libgtk-3-0 libnspr4 libpango-1.0-0 libpangocairo-1.0-0 libstdc++6 libx11-6 libx11-xcb1 libxcb1 libxcomposite1 libxcursor1 libxdamage1 libxext6 libxfixes3 libxi6 libxrandr2 libxrender1 libxss1 libxtst6 ca-certificates fonts-liberation libnss3 lsb-release xdg-utils wget
+```
+
+Next, you have to use `'--no-sandbox'` mode and also `'--disable-setuid-sandbox'` when launching Puppeteer. This can be done by passing them as an arguments to your `.launch()` call: `puppeteer.launch({ args: ['--no-sandbox', '--disable-setuid-sandbox'] });`.
+
 #### Tips
 
 By default, Docker runs a container with a `/dev/shm` shared memory space 64MB.