Use .tar.gz zlib in Windows build to match macOS and Linux

[radarhere]

Changes

Pillow/winbuild/build_prepare.py

Lines 161 to 163 in a7338f8

	"zlib": {
	"url": f"https://github.com/zlib-ng/zlib-ng/archive/refs/tags/{V['ZLIBNG']}.zip",
	"filename": f"zlib-ng-{V['ZLIBNG']}.zip",

to use .tar.gz, to match

Pillow/.github/workflows/wheels-dependencies.sh

Lines 73 to 75 in a7338f8

	function build_zlib_ng {
	if [ -e zlib-stamp ]; then return; fi
	fetch_unpack https://github.com/zlib-ng/zlib-ng/archive/$ZLIB_NG_VERSION.tar.gz zlib-ng-$ZLIB_NG_VERSION.tar.gz

This means that only one file is needed in pillow-depends.