Bump github.com/onsi/ginkgo/v2 from 2.20.1 to 2.21.0 #116

Job	Run time
Check whether tests need to be run based on diff	21s
Verify docs and spelling	40s
Unit test (windows-2022)	13m 40s
Golangci-lint (ubuntu-latest)	9m 2s
Integration test	5m 48s
Unit test (ubuntu-latest)	7m 49s
Go benchmark test	5m 13s
Build Antrea and antctl binaries	12m 57s
Golangci-lint (macos-latest)	7m 19s
Check tidy, code generation and manifest	4m 18s
Build Antrea Windows binaries	2m 17s
	1h 9m 24s

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