gnu: Pin old pybind11 version.

* gnu/packages/python-xyz.scm (pybind11): Move definition to (pybind11-2).
(python-awkward-cpp, python-contourpy, python-hnswlib, python-dm-tree,
python-matplotlib, python-pikepdf, python-optree, python-fusepy): Change
reference to pybind11-2.

* gnu/packages/astronomy.scm (aoflagger, python-galsim, python-pyclp),
  gnu/packages/bioinformatics.scm (python-metacells, python-strawc,
  python-coolbox, python-pyspoa, python-scvelo),
  gnu/packages/chemistry.scm (avogadrolibs),
  gnu/packages/computer-architecture.scm (gem5),
  gnu/packages/duckdb.scm (python-duckdb),
  gnu/packages/electronics.scm (nextpnr, prjtrellis),
  gnu/packages/engineering.scm (python-orocos-kinematics-dynamics),
  gnu/packages/geo.scm (ogs-serial),
  gnu/packages/graphics.scm (openshadinglanguage, openimageio),
  gnu/packages/image-processing.scm (opencolorio),
  gnu/packages/machine-learning.scm (python-fasttext, python-ml-dtypes, onnx,
  onnx-optimizer, onnxruntime, dlib, tensorflow-lite, tensorpipe,
  python-pytorch, python-torchvision, python-ctranslate2, python-hmmlearn,
  python-dlib),
  gnu/packages/maths.scm (python-accupy, python-ducc0),
  gnu/packages/networking.scm (libcamera),
  gnu/packages/opencl.scm (python-pyopencl),
  gnu/packages/package-management.scm (python-libmambapy),
  gnu/packages/physics.scm (python-brille, python-gofit),
  gnu/packages/python-check.scm (python-xdoctest),
  gnu/packages/python-science.scm (pyre, python-boost-histogram, python-cvxpy,
  python-iminuit, python-osqp, python-pyamg, python-qdldl,
  python-scikit-build-core, python-scipy, python-vaex-core, python-pyfma),
  gnu/packages/radio.scm (gnuradio, gr-osmosdr, gr-dsd, gr-iqbal,
  gr-satellites, limesuite-ng),
  gnu/packages/simulation.scm (fenics, python-dolfin-adjoint),
  gnu/packages/statistics.scm (python-diptest, python-george),
  gnu/packages/syndication.scm (syndication-domination): Change reference to pybind11-2.

Change-Id: Ib6abc8580fc2b4c35172f251ff6ba7d80ced4b7b
Signed-off-by: Gabriel Wicki <gabriel@erlikon.ch>

gnu/packages/chemistry.scm

@@ -100,7 +100,7 @@
            mmtf-cpp
            googletest
            pkg-config
-           pybind11))
+           pybind11-2))
     (inputs
       `(("glew" ,glew)
         ("libarchive" ,libarchive)