Rebuild for hdf5 1.12.1

[Anthchirp]

Checklist

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

This also disables Python 3.6 builds

h5py follows NEP-29 and has dropped Python 3.6 support in Oct 2020,
h5py/h5py@0748060, associated PR with more info: h5py/h5py#1727

The conda-forge h5py package does not build on Python 3.6 any more,
conda-forge/h5py-feedstock@70b5c7d

therefore there is no Python 3.6 h5py build for HDF5 1.12.

The solution therefore is to drop Python 3.6 builds downstream, too.
If there has to be a future Python 3.6 build of hdf5plugin then that
may have to go into a feedstock branch.

[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.

[Anthchirp]

@conda-forge-admin, please rerender

[Anthchirp]

@conda-forge-admin, please rerender

[Anthchirp]

Not sure why the linux_ppc64le_python3.9.____cpython build fails with

Failed to load filter blosc: /home/conda/feedstock_root/build_artifacts/hdf5plugin_1632846866921/_test_env_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_place/lib/python3.9/site-packages/hdf5plugin/plugins/libh5blosc.so
.E......
======================================================================
ERROR: testBlosc (hdf5plugin.test.TestHDF5PluginRW)
Write/read test with blosc filter plugin
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/conda/feedstock_root/build_artifacts/hdf5plugin_1632846866921/_test_env_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_place/lib/python3.9/site-packages/hdf5plugin/test.py", line 116, in testBlosc
    self._test('blosc')  # Default options
  File "/home/conda/feedstock_root/build_artifacts/hdf5plugin_1632846866921/_test_env_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_place/lib/python3.9/site-packages/hdf5plugin/test.py", line 72, in _test
    f.create_dataset("data", data=data, chunks=data.shape, **args)
  File "/home/conda/feedstock_root/build_artifacts/hdf5plugin_1632846866921/_test_env_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_place/lib/python3.9/site-packages/h5py/_hl/group.py", line 149, in create_dataset
    dsid = dataset.make_new_dset(group, shape, dtype, data, name, **kwds)
  File "/home/conda/feedstock_root/build_artifacts/hdf5plugin_1632846866921/_test_env_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_place/lib/python3.9/site-packages/h5py/_hl/dataset.py", line 107, in make_new_dset
    dcpl = filters.fill_dcpl(
  File "/home/conda/feedstock_root/build_artifacts/hdf5plugin_1632846866921/_test_env_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_place/lib/python3.9/site-packages/h5py/_hl/filters.py", line 281, in fill_dcpl
    raise ValueError("Unknown compression filter number: %s" % compression)
ValueError: Unknown compression filter number: 32001

[t20100]

Looks weird: Other filters work fine, other versions of python also..

[t20100]

There is an issue with a missing symbol from pthread occuring in this case, so I added link to pthread explicitly.
I fixed it (see silx-kit/hdf5plugin#154), and will prepare a new release.

[Anthchirp]

Thank you for looking into this 👍

[Anthchirp]

Resolved in #31