feat: Drop support for Python 3.9 (#2905)

* chore: drop support for Python 3.9

Signed-off-by: Michele Dolfi <dol@zurich.ibm.com>

* disable CI for python 3.9

Signed-off-by: Michele Dolfi <dol@zurich.ibm.com>

* fix: test bump version

Signed-off-by: Michele Dolfi <dol@zurich.ibm.com>

* add chore to the changelog but without bumping the version

Signed-off-by: Michele Dolfi <dol@zurich.ibm.com>

* force newer langchain-core

Signed-off-by: Michele Dolfi <dol@zurich.ibm.com>

* fix linter for 3.10

Signed-off-by: Michele Dolfi <dol@zurich.ibm.com>

* Add python 3.9 removal notice

Signed-off-by: Christoph Auer <cau@zurich.ibm.com>

* avoid upgrading docling-core

Signed-off-by: Michele Dolfi <dol@zurich.ibm.com>

* restore semantic release settings

Signed-off-by: Michele Dolfi <dol@zurich.ibm.com>

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Signed-off-by: Michele Dolfi <dol@zurich.ibm.com>
Signed-off-by: Christoph Auer <cau@zurich.ibm.com>
Co-authored-by: Christoph Auer <cau@zurich.ibm.com>