Bump minimum required macOS version to 11.7

This commit, as noted in ziglang#20, makes sure that the
correct minimum macOS version is asserted
at the time when someone tries to download
and install the wheels via pip or another
package or dependency management tool.

make_wheels.py

@@ -15,8 +15,8 @@
 ZIG_PYTHON_PLATFORMS = {
     'x86_64-windows': 'win_amd64',
     'x86-windows':    'win32',
-    'x86_64-macos':   'macosx_10_9_x86_64',
-    'aarch64-macos':  'macosx_11_0_arm64',
+    'x86_64-macos':   'macosx_11_7_x86_64',
+    'aarch64-macos':  'macosx_11_7_arm64',
     'i386-linux':     'manylinux_2_12_i686.manylinux2010_i686.musllinux_1_1_i686',
     # renamed i386 to x86 since v0.11.0, i386 was last supported in v0.10.1
     'x86-linux':      'manylinux_2_12_i686.manylinux2010_i686.musllinux_1_1_i686',