Summary

The PR adds cmake code to generate a standard OrbbecSDKConfigVersion.cmake, useful when requesting a specific package version from downstream projects including the library with cmake: find_package(OrbbecSDK 2 REQUIRED). Because the OrbbecSDK v1 library shares exactly the same package name, the only way downstream to differentiate the versions with cmake is by using the standard approach as above.

Current issue that this PR solves

If in a downstream project we do:

find_package(OrbbecSDK)

We may end up with either OrbbecSDK v1 or OrbbecSDK v2 target, if both are installed at the same time.

If we do instead:

find_package(OrbbecSDK 2 REQUIRED)

we would get error like this (even if OrbbecSDK v2 is installed):

$ cmake -DOrbbecSDK_DIR=/opt/OrbbecSDK/lib ..

CMake Error at CMakeLists.txt:703 (FIND_PACKAGE):
  Could not find a configuration file for package "OrbbecSDK" that is
  compatible with requested version "2".

  The following configuration files were considered but not accepted:

    /opt/OrbbecSDK/lib/OrbbecSDKConfig.cmake, version: unknown

Results with this PR

With:

find_package(OrbbecSDK 2 REQUIRED)
message(STATUS "Found OrbbecSDK ${OrbbecSDK_VERSION}")

we then get:

$ cmake -DOrbbecSDK_DIR=/opt/OrbbecSDK/lib ..

...
-- Found OrbbecSDK 2.4.11
...