Make a note for myself or others

[yizhangliu]

Please use pip==21.0.0 when pip install farm-haystack[all]

[masci]

Hi @yizhangliu,

I'm going to close this as there's very little context and the title doesn't explain anything, but if you care to elaborate a bit you can add this note to the docs https://docs.haystack.deepset.ai/docs/get_started