Add seed-isort-config and isort to pre-commit hooks.

Add isort configuration file.

.isort.cfg

@@ -0,0 +1,12 @@
+[settings]
+combine_star=true
+force_sort_within_sections=true
+
+import_heading_stdlib=Standard Python Libraries
+import_heading_thirdparty=Third-Party Libraries
+import_heading_firstparty=cisagov Libraries
+
+# Should be auto-populated by seed-isort-config hook
+known_third_party=
+# These must be manually set to correctly separate them from third party libraries
+known_first_party=

.pre-commit-config.yaml

@@ -60,6 +60,16 @@ repos:
     rev: 19.10b0
     hooks:
       - id: black
+  - repo: https://github.com/asottile/seed-isort-config
+    rev: v1.9.3
+    hooks:
+      - id: seed-isort-config
+  - repo: https://github.com/pre-commit/mirrors-isort
+    # pick the isort version you'd like to use from
+    # https://github.com/pre-commit/mirrors-isort/releases
+    rev: v4.3.21
+    hooks:
+      - id: isort
   - repo: https://github.com/ansible/ansible-lint.git
     rev: v4.1.1a5
     hooks: