Cannot build on Arch Linux because of CMake version

Hello !

retdec seems to not be buildable with recent cmake versions:
```
CMake Error at CMakeLists.txt:3 (cmake_minimum_required):
Compatibility with CMake < 3.5 has been removed from CMake.

Update the VERSION argument value. Or, use the ... syntax
to tell CMake that the project requires at least but has been updated
to work with policies introduced by or earlier.

Or, add -DCMAKE_POLICY_VERSION_MINIMUM=3.5 to try configuring anyway.
```

I tested this PR https://github.com/avast/retdec/pull/1232 which fixed the issue

Start with CMakeLists.txt:3 and reproduce the configuration failure using a recent CMake version on Arch Linux. Review pull request #1232, then verify that the project configures and builds successfully without the reported compatibility error.

Written by the indexing model from the issue text.