python-schema: drop contextlib2 dependency

Upstream only requires contextlib2 on Python <3.3, so it is never
pulled in on a Python 3.14 runtime.

schema builds through the setuptools.build_meta legacy backend but never
declared setuptools as a build dependency; it was only present in the host
build env transitively via contextlib2's build. Add python-setuptools/host
explicitly so the build no longer relies on that side effect.

Signed-off-by: Alexandru Ardelean <alex@shruggie.ro>

lang/python/python-schema/Makefile

@@ -6,7 +6,7 @@ include $(TOPDIR)/rules.mk
 
 PKG_NAME:=python-schema
 PKG_VERSION:=0.7.8
-PKG_RELEASE:=1
+PKG_RELEASE:=2
 PKG_MAINTAINER:=Josef Schlehofer <pepe.schlehofer@gmail.com> 
 
 PYPI_NAME:=schema
@@ -15,6 +15,8 @@ PKG_HASH:=e86cc08edd6fe6e2522648f4e47e3a31920a76e82cce8937535422e310862ab5
 PKG_LICENSE:=MIT
 PKG_LICENSE_FILES:=LICENSE-MIT
 
+PKG_BUILD_DEPENDS:=python-setuptools/host
+
 include ../pypi.mk
 include $(INCLUDE_DIR)/package.mk
 include ../python3-package.mk
@@ -25,7 +27,7 @@ define Package/python3-schema
   SUBMENU:=Python
   URL:=https://github.com/keleshev/schema
   TITLE:=Simple data validation library
-  DEPENDS:=+python3-light +python3-contextlib2
+  DEPENDS:=+python3-light
 endef
 
 define Package/python3-schema/description