Prepare for Crypto++ 8.6 release

Readme.txt

@@ -294,6 +294,31 @@ documentation is one of the highest returns on investment.
 The items in this section comprise the most recent history. Please see History.txt
 for the record back to Crypto++ 1.0.
 
+8.6.0 - September 21, 2021
+ - minor release, recompile of programs required
+ - expanded community input and support
+ * 74 unique contributors as of this release
+ - fix ElGamal encryption
+ - fix ChaCha20 AVX2 implementation
+ - add octal and decimal literal prefix parsing to Integer
+ - add missing overload in ed25519Signer and ed25519Verifier
+ - make SHA-NI independent of AVX and AVX2
+ - fix OldRandomPool GenerateWord32
+ - use CPPFLAGS during feature testing
+ - fix compile on CentOS 5
+ - fix compile on FreeBSD
+ - fix feature testing on ARM A-32 and Aarch64
+ - enable inline ASM for CRC and PMULL on Apple M1
+ - fix Intel oneAPI compile
+ - rename test files with *.cpp extension
+ - fix GCC compile error due to missing _mm256_set_m128i
+ - add LSH-256 and LSH-512 hash functions
+ - add ECIES_P1363 for backwards compatibility
+ - fix AdditiveCipherTemplate<T> ProcessData
+ - remove CRYPTOPP_NO_CXX11 define
+ - add -fno-common for Darwin builds
+ - update documentation
+
 8.5.0 - March 7, 2021
  - minor release, no recompile of programs required
  - expanded community input and support