Set project version and shared library soname thanks to @drew-parsons.

Update README

This release contains:

* New features:
Allow compilation in ILP64 mode, @albandil PR Reference-ScaLAPACK#19

* Major bug fixes:
Use pointer macro to prevent integer overflow, @luszczek PR Reference-ScaLAPACK#16
Fix argument mismatches for implicitly defined functions (for gcc-10 compatibility), @dev-zero PR Reference-ScaLAPACK#26
No memory leaks on blacs_exit, @zerothi PR Reference-ScaLAPACK#37

Merge pull request Reference-ScaLAPACK#41 from e-kwsm/ansi

refactor: replace obsolescent K&R syntax

CMake version update

Closing Reference-ScaLAPACK#15

Release 2.0.2

Release 2.0.1