FIX Allow values less than 1 for the gamma param of spectral clustering

[nicolasdalsass]

What does this implement/fix? Explain your changes.

In scikit-learn 1.1.0, the gamma value for spectral clustering was forced >=1.0
This is incorrect as low values (< 1) are very useful (and almost standard in fact)

This reallows >=0 values instead of >=1 real values

Any other comments?

This is fixed by 46623ef for versions >= 1.2.0 so there is no need to apply this on other branches

[glemaitre]

I am afraid that we are not going to make an new bug fixes release for 1.1.X.
This is fixed in scikit-learn 1.2.X+, so you can update scikit-learn.