Update requirements.txt with joblib<1.2 to solve #565

[giacomorebecchi]

Hi, I'm a BuildNN data scientist. While using HDBSCAN, I encountered issue #565 due to the minor update in joblib=1.2 that does not ensure retrocompatibility. I solved the problem specifying the joblib version to be lower than 1.2.

[jcfaracco]

Lower versions of joblib (<1.2.0) are affected by CVE-2022-21797.

[whymauri]

Have you considered using HDBSAN 0.8.29 with Joblib 1.2.0? This avoids the compatibility issue and the critical CVE in Joblib <1.2.0