Update devcontainer settings for pytest configuration and formatting

Author: iMicknl

.devcontainer/devcontainer.json

@@ -20,8 +20,17 @@
 				"ms-python.python",
 				"yzhang.markdown-all-in-one"
 			],
-			"settings": {
-				"python.defaultInterpreterPath": "./.venv/bin/python"
+			"python.testing.pytestArgs": [
+				"tests"
+			],
+			"python.testing.unittestEnabled": false,
+			"python.testing.pytestEnabled": true,
+			"[python]": {
+				"editor.formatOnSave": true,
+				"editor.defaultFormatter": "charliermarsh.ruff",
+				"editor.codeActionsOnSave": {
+					"source.organizeImports.ruff": "explicit"
+				}
 			}
 		}
 	}