Aleš Hrabalík

Fix conan install by specifiyng zlib version

1

- fixes #215 - 'fltk/1.3.8' requires 'zlib/1.2.11' - 'libxml2/2.9.12' requires 'zlib/1.2.12' - to resolve the conflict, specify 'zlib/1.2.12' in the conanfile

conan install fails due to zlib version conflict

1

Used the template, but all the initial CI jobs fail due to an error in "Configure CMake" step. ``` ERROR: Conflict in fltk/1.3.8: 'fltk/1.3.8' requires 'zlib/1.2.11' while 'libxml2/2.9.12' requires 'zlib/1.2.12'....