ext: Update pybind11 to version 2.6.2.

This should help reduce warning spew when building with newer compilers.
The pybind11::module type has been renamed pybind11::module_ to avoid
conflicts with c++20 modules, according to the pybind11 changelog, so
this CL also updates gem5 source to use the new type. There is
supposedly an alias pybind11::module which is for compatibility, but we
still get linker errors without changing to pybind11::module_.

Change-Id: I0acb36215b33e3a713866baec43f5af630c356ee
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/40255
Maintainer: Bobby R. Bruce <bbruce@ucdavis.edu>
Reviewed-by: Bobby R. Bruce <bbruce@ucdavis.edu>
Tested-by: kokoro <noreply+kokoro@google.com>

ext/pybind11/setup.cfg

@@ -1,6 +1,54 @@
+[metadata]
+long_description = file: README.rst
+long_description_content_type = text/x-rst
+description = Seamless operability between C++11 and Python
+author = Wenzel Jakob
+author_email = wenzel.jakob@epfl.ch
+url = https://github.com/pybind/pybind11
+license = BSD
+
+classifiers =
+    Development Status :: 5 - Production/Stable
+    Intended Audience :: Developers
+    Topic :: Software Development :: Libraries :: Python Modules
+    Topic :: Utilities
+    Programming Language :: C++
+    Programming Language :: Python :: 2.7
+    Programming Language :: Python :: 3
+    Programming Language :: Python :: 3.5
+    Programming Language :: Python :: 3.6
+    Programming Language :: Python :: 3.7
+    Programming Language :: Python :: 3.8
+    Programming Language :: Python :: 3.9
+    License :: OSI Approved :: BSD License
+    Programming Language :: Python :: Implementation :: PyPy
+    Programming Language :: Python :: Implementation :: CPython
+    Programming Language :: C++
+    Topic :: Software Development :: Libraries :: Python Modules
+
+keywords =
+    C++11
+    Python bindings
+
+[options]
+python_requires = >=2.7, !=3.0, !=3.1, !=3.2, !=3.3, !=3.4
+zip_safe = False
+
 [bdist_wheel]
 universal=1
 
+[check-manifest]
+ignore =
+    tests/**
+    docs/**
+    tools/**
+    include/**
+    .*
+    pybind11/include/**
+    pybind11/share/**
+    CMakeLists.txt
+
+
 [flake8]
 max-line-length = 99
 show_source = True
@@ -10,3 +58,28 @@ ignore =
     E201, E241, W504,
     # camelcase 'cPickle' imported as lowercase 'pickle'
     N813
+    # Black conflict
+    W503, E203
+
+[mypy]
+files = pybind11
+python_version = 2.7
+warn_unused_configs = True
+
+# Currently (0.800) identical to --strict
+disallow_any_generics = True
+disallow_subclassing_any = True
+disallow_untyped_calls = True
+disallow_untyped_defs = True
+disallow_incomplete_defs = True
+check_untyped_defs = True
+disallow_untyped_decorators = True
+no_implicit_optional = True
+warn_redundant_casts = True
+warn_unused_ignores = True
+warn_return_any = True
+no_implicit_reexport = True
+strict_equality = True
+
+[tool:pytest]
+timeout = 300