Set python_min following CFEP-25

Using minimum python_requires defined at https://github.com/Lightning-AI/litdata/blob/v0.2.30/setup.py#L70. See details of CFEP-25 at conda-forge/conda-forge.github.io#2351 and https://conda-forge.org/docs/maintainer/knowledge_base/#noarch-python

recipe/meta.yaml

@@ -1,5 +1,6 @@
 {% set name = "litdata" %}
 {% set version = "0.2.30" %}
+{% set python_min = python_min|default("3.8") %}
 
 package:
   name: {{ name|lower }}
@@ -17,15 +18,15 @@ build:
 requirements:
   host:
     - pip
-    - python >=3.8
+    - python {{ python_min }}.*
     - setuptools
     - wheel
   run:
     - boto3
     - filelock
     - lightning-utilities
     - numpy
-    - python >=3.8
+    - python >={{ python_min }}
     - pytorch
     - requests
 
@@ -38,6 +39,7 @@ test:
     - python -c "import numpy as np; from litdata.streaming.serializers import NoHeaderNumpySerializer; serializer = NoHeaderNumpySerializer(); assert serializer.can_serialize(np.ones((10,)))"
   requires:
     - pip
+    - python ={{ python_min }}
 
 about:
   home: https://github.com/Lightning-AI/litdata