Update copyright year in LICENSE #855

Job	Run time
Format	53s
Documentation	1m 24s
Julia 1.0 - ubuntu-latest - x64 - push	1m 2s
Julia 1.0 - ubuntu-latest - x86 - push	1m 23s
Julia 1.0 - macOS-latest - x64 - push	1m 41s
Julia 1.0 - windows-latest - x64 - push	3m 59s
Julia 1.0 - windows-latest - x86 - push	4m 15s
Julia 1.6 - ubuntu-latest - x64 - push	20s
Julia 1.6 - ubuntu-latest - x86 - push	20s
Julia 1.6 - macOS-latest - x64 - push	1m 0s
Julia 1.6 - windows-latest - x64 - push	4m 42s
Julia 1.6 - windows-latest - x86 - push	7m 54s
Julia nightly - ubuntu-latest - x64 - push	32s
Julia nightly - ubuntu-latest - x86 - push	33s
Julia nightly - macOS-latest - x64 - push	1m 13s
Julia nightly - windows-latest - x64 - push	52s
Julia nightly - windows-latest - x86 - push	50s
	32m 53s

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