Update OPENJDK_TAG to merged level jdk-11.0.21+6 #82

Job	Run time
Select platforms	1s
linux-x64-hs-nopch / build (debug)	1m 53s
linux-x86 / build (debug)	2m 19s
linux-x86 / build (release)	2m 1s
linux-x64 / build (debug)	1m 54s
linux-x64 / build (release)	1m 40s
linux-x64-hs-minimal / build (debug)	1m 52s
linux-x64-hs-optimized / build (debug)	1m 46s
linux-x64-hs-zero / build (debug)	1m 43s
macos-aarch64 / build (debug)	3m 49s
macos-aarch64 / build (release)	3m 56s
macos-x64 / build (debug)	3m 42s
macos-x64 / build (release)	3m 53s
windows-aarch64 / build (debug)	4m 14s
windows-aarch64 / build (release)	3m 26s
windows-x64 / build (debug)	3m 31s
windows-x64 / build (release)	3m 30s
linux-x64	0s
linux-cross-compile	0s
linux-x86	0s
windows-x64	0s
macos-x64	0s
Remove bundle artifacts	5s
	45m 15s

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