Update our build script to publish Mac aarch_64 binaries (#9203)

These are still x86-64 binaries at the moment (see #8557), but should be
usable on M1 Macs in the Rosetta compatibility mode. Let's start
publishing them on our GitHub release page and then eventually we can
make them into true aarch_64 binaries.

This fixes #9200.

Author: acozzette

protoc-artifacts/build-zip.sh

@@ -16,6 +16,7 @@ release page. If the target is protoc, well-known type .proto files will also be
 included. Each invocation will create 8 zip packages:
   dist/<TARGET>-<VERSION_NUMBER>-win32.zip
   dist/<TARGET>-<VERSION_NUMBER>-win64.zip
+  dist/<TARGET>-<VERSION_NUMBER>-osx-aarch_64.zip
   dist/<TARGET>-<VERSION_NUMBER>-osx-x86_64.zip
   dist/<TARGET>-<VERSION_NUMBER>-linux-x86_32.zip
   dist/<TARGET>-<VERSION_NUMBER>-linux-x86_64.zip
@@ -33,6 +34,7 @@ VERSION_NUMBER=$2
 declare -a FILE_NAMES=( \
   win32.zip windows-x86_32.exe \
   win64.zip windows-x86_64.exe \
+  osx-aarch_64.zip osx-aarch_64.exe \
   osx-x86_64.zip osx-x86_64.exe \
   linux-x86_32.zip linux-x86_32.exe \
   linux-x86_64.zip linux-x86_64.exe \