Update Changelog with 0.3.12 changes

Changelog.txt

@@ -1,4 +1,31 @@
 OpenBLAS ChangeLog
+====================================================================
+Version 0.3.12
+ 24-Oct-2020
+
+common:
+	* Fixed missibg LAPACK functions (inadvertently dropped during
+	  the build system restructuring)
+	* Fixed argument conversion macro in LAPACKE_zgesvdq (LAPACK #458)
+
+POWER:
+	* Added optimized SCOPY/CCOPY kernels for POWER10
+	* Increased and unified the default size of the GEMM BUFFER
+	* Fixed building for POWER1ß in DYNAMIC_ARCH mode
+	* POWER10 compatibility test now checks binutils version as well
+	* Cleaned up compiler warnings
+
+x86_64:
+	* corrected compiler version checks for AVX2 compatibility
+	* added compiler option -mavx2 for building with flang
+	* fixed direct SGEMM pathway for small matrix sizes (broken by
+	  the code refactoring in 0.3.11)
+	* fixed unhandled partial register clobbers in several kernels
+	  for AXPY,DOT,GEMV_N and GEMV_T flagged by gcc10 tree-vectorizer
+
+ARMV8:
+	* improved Apple Vortex support to include cross-compiling
+
 ====================================================================
 Version 0.3.11
  17-Oct-2020
@@ -28,7 +55,7 @@ Version 0.3.11
 	* Makefile builds no longer misread NO_CBLAS=0 or NO_LAPACK=0 as 
 	  enabling these options
 	* Fixed detection of gfortran when invoked through an mpi wrapper
-	* Improve thread reinitialization performance with OpenMP xafter a fork 
+	* Improve thread reinitialization performance with OpenMP after a fork 
 	* Added support for building only the subset of the library required
 	  for a particular precision by specifying BUILD_SINGLE, BUILD_DOUBLE
 	* Optional function name prefixes and suffixes are now correctly
@@ -66,7 +93,6 @@ ARMV8:
 	* Fixed cpu detection on BSD-like systems
 	* Fixed compilation in -std=C18 mode
 
-
 IBM Z:
 	* Added support for compiling with the clang compiler
 	* Improved GEMM performance on Z14