[R] Update note about `qs` serialization #11545

Job	Run time
Build libxgboost4j.so with CUDA	6m 46s
Build libxgboost4j.so targeting glibc 2.17 (arch aarch64, runner linux-arm64-cpu)	1m 41s
Build libxgboost4j.dylib for MacOS (Apple Silicon)	1m 37s
Build libxgboost4j.so targeting glibc 2.17 (arch x86_64, runner linux-amd64-cpu)	1m 54s
Build and test JVM packages (Linux, Scala 2.12)	10m 28s
Build libxgboost4j.dylib for MacOS (Intel)	5m 9s
Build and test JVM packages (Linux, Scala 2.13)	4m 59s
Build and test JVM packages (windows-latest)	10m 6s
Build and test JVM packages (macos-13)	11m 42s
Test JVM packages with CUDA (Scala 2.12)	6m 18s
Build docs for JVM packages	4m 39s
Test JVM packages with CUDA (Scala 2.13)	6m 10s
Deploy JVM packages to S3 (cpu)	9s
Deploy JVM packages to S3 (cpu)	9s
Deploy JVM packages to S3 (gpu)	9s
Deploy JVM packages to S3 (gpu)	9s
	1h 12m 5s

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