renovate: Change stategy to update-lockfile

Support for this strategy was added recently:
renovatebot/renovate#22820. It seems that at the same
time the behavior of the "replace" strategy changed, causing PRs to be opened
with unnecessary changes to Cargo.toml.

Author: nicholasbishop

.github/renovate.json

@@ -10,7 +10,7 @@
       "on wednesday"
     ]
   },
-  "rangeStrategy": "replace",
+  "rangeStrategy": "update-lockfile",
   "schedule": [
     "on wednesday"
   ]