chore: reorganize Python version-specific dependencies and remove redundant entries

Author: ahnv

requirements/requirements.txt

@@ -1,11 +1,8 @@
 requests_toolbelt>=1.0.0
-urllib3<3
 
-# ------------ Python >= 3.9 ------------
-requests>=2.32.2; python_version >= "3.9"
+urllib3<3; python_version >= "3.9"
+urllib3!=2.0.0,<3; python_version < "3.9"
 
-# ------------ 3.7 <= Python < 3.9 ------------
+requests>=2.32.2; python_version >= "3.9"
 requests>=2.22.0,<2.32; python_version >= "3.7" and python_version < "3.9"
-
-# ------------ Python < 3.7 ------------
 requests>=2.22.0,<2.28; python_version < "3.7"

requirements/test.txt

@@ -1,20 +1,16 @@
 requests_toolbelt>=1.0.0
-urllib3<3
+urllib3<3; python_version >= "3.9"
+urllib3!=2.0.0,<3; python_version < "3.9"
 
-# ------------ Python >= 3.9 ------------
 requests>=2.32.2; python_version >= "3.9"
+requests>=2.22.0,<2.32; python_version >= "3.7" and python_version < "3.9"
+requests>=2.22.0,<2.28; python_version < "3.7"
+
 coverage>=7.6.0; python_version >= "3.13"
 coverage>=7.5.0; python_version >= "3.9" and python_version < "3.13"
-
-# ------------ 3.7 <= Python < 3.9 ------------
-requests>=2.22.0,<2.32; python_version >= "3.7" and python_version < "3.9"
 coverage>=5.0,<7.0; python_version >= "3.7" and python_version < "3.9"
-
-# ------------ Python < 3.7 ------------
-requests>=2.22.0,<2.28; python_version < "3.7"
 coverage==4.5.4; python_version < "3.7"
 
-# ------------ responses versions ------------
 responses>=0.25.0; python_version >= "3.8"
 responses>=0.18.0,<0.25; python_version >= "3.7" and python_version < "3.8"
 responses<0.18.0; python_version < "3.7"