gRPC-Core Release 1.48.0

[yas...@google.com]

This is 1.48.0([g](https://github.com/grpc/grpc/blob/master/doc/g_stands_for.md)arum) release announcement for gRPC-Core and the wrapped languages C++, C#, Objective-C, Python, PHP and Ruby. Latest release notes are [here](https://github.com/grpc/grpc/releases/tag/v1.48.0).

This release contains refinements, improvements, and bug fixes, with highlights listed below.

Core

• Upgrade Abseil to LTS 20220623.0 . (#30155)
• Call: Send cancel op down the stack even when no ops are sent. (#30004)
• FreeBSD system roots implementation. (#29436)
• xDS: Workaround to get gRPC clients working with istio. (#29841)

Python

• Set Correct Platform Tag in Wheels on Mac OS with Python 3.10. (#29857)
• [Aio] Ensure Core channel closes when deallocated. (#29797)
• [Aio] Fix the wait_for_termination return value. (#29795)

Ruby

• Make the gem build on TruffleRuby. (#27660)
• Support for prebuilt Ruby binary on x64-mingw-ucrt platform. (#29684)
• [Ruby] Add ruby_abi_version to exported symbols. (#28976)

Objective-C

First developer preview of XCFramework binary distribution via Cocoapod (#28749). This brings in significant speed up to local compile time and includes support for Apple Silicon build.

• The following binary pods are made available for ObjC V1 & V2 API
  • gRPC-XCFramework (source pod gRPC)
  • gRPC-ProtoRPC-XCFramework (source pod gRPC-ProtoRPC)
• The following platforms and architectures are included
  • ios: armv7, arm64 for device. arm64, i386, x86_64 for simulator
  • macos: x86_64 (Intel), arm64 (Apple Silicon)