Added py-spdlog package (#14514)

* Added py-spdlog package

* pleasing flake-8

* pleasing flake-8

* addressed some comments from adamjstewart

* changed URL for archive

* replaced with pypi.io url

var/spack/repos/builtin/packages/py-spdlog/package.py

+# Copyright 2013-2020 Lawrence Livermore National Security, LLC and other
+# Spack Project Developers. See the top-level COPYRIGHT file for details.
+#
+# SPDX-License-Identifier: (Apache-2.0 OR MIT)
+
+from spack import *
+
+
+class PySpdlog(PythonPackage):
+    """The py-spdlog package provides a Python wrapper
+    to the C++ spdlog library."""
+
+    homepage = 'https://github.com/bodgergely/spdlog-python'
+    url = 'https://pypi.io/packages/source/s/spdlog/spdlog-2.0.0.tar.gz'
+    git = 'https://github.com/bodgergely/spdlog-python.git'
+
+    # NOTE: Righ now py-spdlog works with a git submodule containing a copy
+    # of spdlog. Ideally we would want to install spdlog ourselves and make
+    # this package depend on it. There is an issue for that on the py-spdlog
+    # github repository: https://github.com/bodgergely/spdlog-python/issues/19
+
+    version('master', branch='master', submodules=True)
+    version('2.0.0', sha256='b8d3732839850da414a47e91547ee1246f0690cb83f43f11a1fbaec40b7b968c')
+
+    depends_on('py-pybind11@2.2:', type=('build', 'run'))
+    depends_on('py-setuptools', type='build')
+    depends_on('py-pytest-runner', type='build')
+    depends_on('py-pytest', type='test')