Added .codegen.json for automated release infra (#743)

Author: nfx

.codegen.json

@@ -0,0 +1,10 @@
+{
+  "version": {
+    "src/databricks/labs/ucx/__about__.py": "__version__ = \"$VERSION\""
+  },
+  "toolchain": {
+    "required": ["hatch"],
+    "pre_setup": ["hatch env create"],
+    "prepend_path": ".venv/bin"
+  }
+}