Release v1.6.0

Features:
- Option for minimal password length for password recovery
- Implement exhaustive password search
- Continue password search if found password does not use expected
  character set
- Options to resume an interrupted attack or password recovery

Packaging:
- Removed OpenMP dependency, use standard C++ threads instead

CMakeLists.txt

@@ -2,7 +2,7 @@ cmake_minimum_required(VERSION 3.16)
 
 # project definition
 project(bkcrack
-    VERSION 1.5.0
+    VERSION 1.6.0
     DESCRIPTION "Crack legacy zip encryption with Biham and Kocher's known plaintext attack."
     HOMEPAGE_URL "https://github.com/kimci86/bkcrack"
     LANGUAGES CXX)