* Fix Ruby Windows 3.1 (x64-mingw-ucrt) build:
- Pass-in CPPFLAG "GPR_WINDOWS_UCRT" to pickup correct shared object file.
- Rename intermediate legacy SO file from 'grpc_c.64.ruby' to 'grpc_c.64-msvcrt.ruby' for clarity.
- Add artifact target for Ruby x64-mingw-ucrt
* Change CPP flag name
* upgrade ruby docker images to debian 11
* upgrade C# docker images to debian11
* update sanity dockerimage to debian11
* upgrade cxx interop to debian11
* add ccache to python interop images
* enable use of ccache for interop tests
* adjust run_tests.py to new docker images
* add ccache to rake-compiler-dock docker images
* improve prepare_ccache_symlinks_rc
* enable use of ccache in rake-compiler-dock docker containers
* add ccache support for python_manylinux2014_aarch64
* add ccache support for python_linux_armv7
* deduplicate python3.9 install
* ccache for crosscompiled darwin gems is broken
* fix bash -l resetting of PATH in grpc_artifact_python_linux_armv7
apolcyn
Johnny Shields
Jan Tattermusch
Esun Kim