remove version restriction

[melund]

Checklist

• Used a fork of the feedstock to propose changes
• Bumped the build number (if the version is unchanged)
• Reset the build number to 0 (if the version changed)
• Re-rendered with the latest conda-smithy (Use the phrase @conda-forge-admin, please rerender in a comment in this PR for automated rerendering)
• Ensured the license file is being packaged.

[conda-forge-linter]

Hi! This is the friendly automated conda-forge-linting service.

I just wanted to let you know that I linted all conda-recipes in your PR (recipe) and found it was in an excellent condition.

[melund]

@conda-forge-admin, please rerender

[melund]

@jjnurminen It didn't seem to work. I will just try to remove the python3 patch when building on 2.7.

[melund]

@jjnurminen It fails with a CMAKE problem. I guess it can be solved, but I don't have time :)

CMake Error at D:/bld/btk_1579008878392/_build_env/Library/share/cmake-3.16/Modules/FindPackageHandleStandardArgs.cmake:146 (message):
  Could NOT find NumPy (missing: NUMPY_VERSION NUMPY_INCLUDE_DIR)
Call Stack (most recent call first):
  D:/bld/btk_1579008878392/_build_env/Library/share/cmake-3.16/Modules/FindPackageHandleStandardArgs.cmake:393 (_FPHSA_FAILURE_MESSAGE)
  CMake/FindNumPy.cmake:31 (FIND_PACKAGE_HANDLE_STANDARD_ARGS)
  Wrapping/Python/CMakeLists.txt:4 (FIND_PACKAGE)

[jjnurminen]

Ok, thanks a lot for your efforts. Maybe I'll dig into it at some point.