Release 2.12

Set comment on lcms2.h to version 2.12
Update change log

Author: mm2

ChangeLog

@@ -4,7 +4,7 @@
 -----------------------
 Added new build-in sigmoidal tone curve
 Added XCode 12 project
-Addes support for multichannel input up to 15 channels
+Added support for multichannel input up to 15 channels
 Fix LUT8 write matrix
 Fix version mess on 10/11
 Fix tools & samples xgetopt
@@ -15,6 +15,7 @@ plugin: add lab to any on float
 plugin: it can now be compiled as C++
 recover PDF documentation, but try to keep it under a resonable size.
 Prevent a rare but possible out-of-bounds read in postscript generator
+Remove unused variables
 
 -----------------------
 2.11 Maintenance release

include/lcms2.h

@@ -23,7 +23,7 @@
 //
 //---------------------------------------------------------------------------------
 //
-// Version 2.12rc2
+// Version 2.12
 //
 
 #ifndef _lcms2_H