isort: merge config into pyproject.toml

Change-Id: I3a50de04897789c7b2f291882faf1c862645b054
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/563141
Tested-by: Mike Frysinger <vapier@google.com>
Reviewed-by: Gavin Mak <gavinmak@google.com>
Commit-Queue: Mike Frysinger <vapier@google.com>

pyproject.toml

@@ -16,6 +16,30 @@
 line-length = 80
 target-version = ['py36', 'py37', 'py38', 'py39', 'py310', 'py311'] #, 'py312'
 
+# Config file for the isort python module.
+# This is used to enforce import sorting standards.
+#
+# https://pycqa.github.io/isort/docs/configuration/options.html
+[tool.isort]
+# Be compatible with `black` since it also matches what we want.
+profile = 'black'
+
+line_length = 80
+length_sort = false
+force_single_line = true
+lines_after_imports = 2
+from_first = false
+case_sensitive = false
+force_sort_within_sections = true
+order_by_type = false
+
+# Ignore generated files.
+extend_skip_glob = '*_pb2.py'
+
+# Allow importing multiple classes on a single line from these modules.
+# https://google.github.io/styleguide/pyguide#s2.2-imports
+single_line_exclusions = ['abc', 'collections.abc', 'typing']
+
 [tool.pytest.ini_options]
 markers = """
     skip_cq: Skip tests in the CQ. Should be rarely used!