add rudimentary support for PEP 518, configure black + isort in pypro…

…ject.toml

Signed-off-by: oleg.hoefling <oleg.hoefling@gmail.com>

pyproject.toml

@@ -0,0 +1,33 @@
+[tool.black]
+line_length = 130
+skip-string-normalization = true
+target_version = ['py38']
+include = '\.pyi?$'
+exclude = '''
+
+(
+  /(
+      \.eggs         # exclude a few common directories in the
+    | \.git          # root of the project
+    | \.mypy_cache
+    | \.tox
+    | build
+    | dist
+  )/
+)
+'''
+
+[tool.isort]
+force_alphabetical_sort_within_sections = true
+recursive = true
+line_length = 130
+multi_line_output = 3
+include_trailing_comma = true
+force_grid_wrap = 0
+use_parentheses = true
+combine_as_imports = true
+known_first_party = ['xmlsec']
+known_third_party = ['lxml', 'pytest', '_pytest', 'hypothesis']
+
+[build-system]
+requires = ['setuptools>=42', 'wheel', 'setuptools_scm[toml]>=3.4']