catch exceptions as const

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: Id11e5c601ff495cd61abd3c35e6558e446e8a7d1
diff --git a/serialize.cpp b/serialize.cpp
index 7bde9b7..5982093 100644
--- a/serialize.cpp
+++ b/serialize.cpp
@@ -68,7 +68,7 @@
         cereal::JSONInputArchive iarchive(is);
         iarchive(savedGroups);
     }
-    catch (cereal::Exception& e)
+    catch (const cereal::Exception& e)
     {
         lg2::error("Failed to restore groups, ERROR = {ERROR}", "ERROR", e);
         fs::remove(path);