PyMC-Marketing favicon

[wd60622]

The website favicon is "Schedule a Free Strategy Consultation" which appears to be the first header in the index.md

pymc-marketing/docs/source/index.md

Lines 38 to 40 in 0aac525

	## 📞 Schedule a Free Strategy Consultation

I don't think this is ideal. It might be 🚀 PyMC-Marketing using the PyMC-Marketing logo or something

Related to #1074