Add wheels for google-cloud-logging dependencies.

BUG=chromium:1138969
TEST=`create_venv3 chromite/venv/requirements.txt`

These changes down-version google_api_core to 1.19.0
and protobuf to 3.11.3, to match current ebuild constraints.
I downloaded google_auth 1.14 to avoid downloading the very latest
because google_api_core 1.19.0 only needs google_auth 1.14.0.
Note that we already have protobuf 3.11.3 in the tree, so no packages
were needed for this.

I verified this with running
 pip download --only-binary=:all: -r ../chromite/venv/requirements.txt -d pip_packages/ --find-links pip_packages/
and it only installed one additional package (grpcio-1.33) but
said that was to satisfy grpcio>=1.0rc1, but we are currently on
1.0.0.

pip download commands used:
 pip download --python-version 36 --abi cp36m "google_api_core==1.19.0" --only-binary=:all: --dest=pip_packages
 pip download --python-version 36 --abi cp36m "protobuf==3.11.3" --only-binary=:all: --dest=pip_packages
 pip download --python-version 36 --abi cp36m "google_auth==1.14.0" --only-binary=:all: --dest=pip_packages

Additional files pulled in from new pinned versions in requirements.txt,
which will be a follow-on CL.

Change-Id: If68bc9cf74f8b5ee0e3c0e8a023b095fab81959b
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/infra_virtualenv/+/2481614
Reviewed-by: Chris McDonald <cjmcdonald@chromium.org>
Tested-by: Michael Mortensen <mmortensen@google.com>
Commit-Queue: Michael Mortensen <mmortensen@google.com>
diff --git a/pip_packages/google_api_core-1.19.0-py2.py3-none-any.whl b/pip_packages/google_api_core-1.19.0-py2.py3-none-any.whl
new file mode 100644
index 0000000..18c2fe4
--- /dev/null
+++ b/pip_packages/google_api_core-1.19.0-py2.py3-none-any.whl
Binary files differ
diff --git a/pip_packages/google_auth-1.14.0-py2.py3-none-any.whl b/pip_packages/google_auth-1.14.0-py2.py3-none-any.whl
new file mode 100644
index 0000000..1d1abc8
--- /dev/null
+++ b/pip_packages/google_auth-1.14.0-py2.py3-none-any.whl
Binary files differ