Fully revert cmake version string change

Author: milot-mirdita

Diff for: CMakeLists.txt

@@ -1,6 +1,4 @@
-cmake_minimum_required(VERSION 3.0 FATAL_ERROR)
-cmake_policy(SET CMP0060 OLD)
-cmake_policy(SET CMP0074 NEW)
+cmake_minimum_required(VERSION 2.8.12 FATAL_ERROR)
 project(MMseqs CXX C)
 message("-- Source Directory: ${CMAKE_CURRENT_SOURCE_DIR}")
 message("-- Project Directory: ${PROJECT_SOURCE_DIR}")