xlsxio: missing CMake package config file

Hey! Please provide a CMake package config file for easier pickup of your library. Resolving this issue would help a lot for picking the library up, because currently one has to write a custom finder.

CMake Warning for this issue:

By not providing "Findxlsxio_read.cmake" in CMAKE_MODULE_PATH this project
  has asked CMake to find a package configuration file provided by
  "xlsxio_read", but CMake did not find one.

  Could not find a package configuration file provided by "xlsxio_read" with
  any of the following names:

    xlsxio_readConfig.cmake
    xlsxio_read-config.cmake

  Add the installation prefix of "xlsxio_read" to CMAKE_PREFIX_PATH or set
  "xlsxio_read_DIR" to a directory containing one of the above files.  If
  "xlsxio_read" provides a separate development package or SDK, be sure it
  has been installed.