How to fix CMake “Could not find a package configuration file provided by “Qt5Core” on Ubuntu?

Problem:

When trying to configure your project using e.g.

cmake .

you see the following error messages:

CMake Warning at CMakeLists.txt:120 (find_package):
  By not providing "FindQt5Core.cmake" in CMAKE_MODULE_PATH this project has
  asked CMake to find a package configuration file provided by "Qt5Core", but
  CMake did not find one.

  Could not find a package configuration file provided by "Qt5Core" with any
  of the following names:

    Qt5CoreConfig.cmake
    qt5core-config.cmake

  Add the installation prefix of "Qt5Core" to CMAKE_PREFIX_PATH or set
  "Qt5Core_DIR" to a directory containing one of the above files.  If
  "Qt5Core" provides a separate development package or SDK, be sure it has
  been installed.

Solution:

Install qtbase5-dev:

sudo apt -y install qtbase5-dev