Bump gunicorn from 20.0.4 to 22.0.0 in /tests/test_gcloud/testbench #3556

Job	Run time
Build Number	0s
Lint	3m 37s
Lint for Docs	11s
Linux	8m 49s
Bazel Linux	43m 35s
macOS	17m 54s
Bazel macOS	36m 55s
Bazel Windows	16m 15s
Wheel ${{ matrix.python }} Windows	0s
Test ${{ matrix.python }} Windows	0s
Nightly ${{ matrix.python }} Windows	0s
Wheel 3.9 macOS	39s
Wheel 3.10 macOS	1m 26s
Wheel 3.11 macOS	46s
Wheel 3.12 macOS	39s
Test 3.9 macOS	1h 17m 4s
Nightly ${{ matrix.python }} macOS	0s
Wheel 3.9 Linux	1m 1s
Wheel 3.10 Linux	3m 42s
Wheel 3.11 Linux	9m 46s
Wheel 3.12 Linux	1m 9s
Test 3.9 Linux	31m 35s
Nightly ${{ matrix.python }} Linux	0s
Release	0s
Nightly	0s
Docker Nightly	0s
Release Candidate	0s
Docker Release	0s
	4h 15m 3s

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