feat: 'auto' option for runPubGetInParallel

[tomassasovsky]

Description

Adds the new value of 'auto' to runPubGetInParallel, which is now default and will only run pub get sequentially if it's being run on a CI instance.

Since the current variable type is of bool for this variable, I had to add some code to handle both the old and new possible data types for parsing. Any alternative ideas for this are more than welcome.

PS: thanks for making such an awesome tool!

Closes #546

Type of Change

• [x] ✨ feat -- New feature (non-breaking change which adds functionality)
• [ ] 🛠️ fix -- Bug fix (non-breaking change which fixes an issue)
• [ ] ❌ ! -- Breaking change (fix or feature that would cause existing functionality to change)
• [ ] 🧹 refactor -- Code refactor
• [ ] ✅ ci -- Build configuration change
• [ ] 📝 docs -- Documentation
• [ ] 🗑️ chore -- Chore

[CLAassistant]

All committers have signed the CLA.

[tomassasovsky]

Changed the docs to reflect the change, but tests are a bit more complicated cause I don't really understand how things are set up there and how everything interacts with each other just yet. I can take a deeper look into it during the week though.