Update to Unicode 15.0

.../GHC/Unicode/Internal/Char/UnicodeData/GeneralCategory.hs

...icode/Internal/Char/UnicodeData/SimpleLowerCaseMapping.hs

...icode/Internal/Char/UnicodeData/SimpleTitleCaseMapping.hs

...icode/Internal/Char/UnicodeData/SimpleUpperCaseMapping.hs

libraries/base/GHC/Unicode/Internal/Version.hs

libraries/base/changelog.md

libraries/base/tests/unicode001.hs

libraries/base/tests/unicode002.stdout

libraries/base/tests/unicode003.stdout

libraries/base/tools/ucd2haskell/README.md

libraries/base/tools/ucd2haskell/unicode_version