Add cred scan suppression for dist utils (microsoft#23251)

Author: karthiknadig

.config/CredScanSuppressions.json

@@ -0,0 +1,11 @@
+{
+    "tool": "Credential Scanner",
+    "suppressions": [
+      {
+        "file": [
+          ".nox/install_python_libs/lib/python3.8/site-packages/setuptools/_distutils/command/register.py"
+        ],
+        "_justification": "These are not real passwords. For documentation purposes only."
+      }
+    ]
+  }