Update version number to `v3.0` #8693

Job	Run time
pre-flight-check	1m 59s
build-test-windows-msvc	1m 54s
build-test-windows-mingw	2m 32s
check-status-of-nightly-action	8s
build-test-ubuntu	1m 46s
build-test-macos-with-address-sanitizer	39s
build-test-ubuntu-32-64-bit-mix-mode	1m 15s
build-test-ubuntu-32-bit	1m 18s
build-test-ubuntu-bazel	1m 4s
build-test-ubuntu-with-address-sanitizer-clang-latest	1m 4s
build-test-ubuntu-with-address-sanitizer-gcc-latest	41s
build-test-ubuntu-with-thread-sanitizer-clang-latest	1m 14s
build-test-unix-with-freebsd	3m 53s
run-integration-test	6m 4s
coverage-and-docs	1m 33s
	27m 4s

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