title: Why does find_package(MPI) generate a warning message?
body: <p>I'm using CMake 3.22.0-rc2. When I run:</p>
  <pre><code>find_package(MPI)
  </code></pre>
  <p>I get the warning:</p>
  <pre><code>CMake Warning (dev) at /opt/versions/cmake/3.22.0-rc2/share/cmake-3.22/Modules/FindPackageHandleStandardArgs.cmake:438 (message):
    The package name passed to `find_package_handle_standard_args` (PkgConfig)
    does not match the name of the calling package (MPI).  This can lead to
    problems in calling code that expects `find_package` result variables
    (e.g., `_FOUND`) to follow a certain pattern.
  Call Stack (most recent call first):
    /opt/versions/cmake/3.22.0-rc2/share/cmake-3.22/Modules/FindPkgConfig.cmake:88 (find_package_handle_standard_args)
    /opt/versions/cmake/3.22.0-rc2/share/cmake-3.22/Modules/FindMPI.cmake:270 (include)
    examples/multi-gpu-programming-models/CMakeLists.txt:2 (find_package)
  This warning is for project developers.  Use -Wno-dev to suppress it.
  </code></pre>
  <p>I realize I can suppress this error, but - does it have anything to do with what I've got in my <code>CMakeLists.txt</code> or is this some sort of internal CMake (semi-)bug?</p>