Free scipy version whenever we update lstchain to a new gammapy release

[rlopezcoto]

#1201 limits scipy to version before 1.12 due to a breaking change solved in gammapy main branch. Let us fix scipy version until there is a gammapy release

[morcuended]

I think scipy was pinned before the release of Gammapy 1.2. Now there is even Gammapy v1.3 out. We do not depend very much on it in the codebase, but especially for some high-level analysis notebooks, we made some changes to adapt to the newer versions 1.2/1.3 and might not work with Gammapy 1.1. The problem is that people may still use older versions, so I'm not sure whether to change the Gammapy version required >=1.2.

[rlopezcoto]

maybe we can adapt lstchain to work with gammapy v1.3 and make a new major release (v0.11)?