Add pre-commit, update flake8, run black

.flake8

@@ -1,2 +1,8 @@
 [flake8]
-ignore = E501, W503
+# Disable some formatted-related warnings that conflict with black's way of
+# formatting code.
+#
+# E203: Whitespace before ':'
+# E501: line too long
+# E701: Multiple statements on one line (colon)
+ignore = E203,E501,E701

.pre-commit-config.yaml

@@ -0,0 +1,8 @@
+# See https://pre-commit.com for more information
+# See https://pre-commit.com/hooks.html for more hooks
+repos:
+  - repo: https://github.com/psf/black-pre-commit-mirror
+    rev: 24.3.0
+    hooks:
+      - id: black
+        files: 'gdb/.*'