docs: Document `ETHEREUM_PARALLEL_BLOCK_RANGES` env var
@@ -30,6 +30,7 @@ in parallel for block retrieval (defaults to 64)
parallel (defaults to 50)
* `ETHEREUM_BLOCK_RANGE_SIZE` - number of blocks to scan for events in
each request (defaults to 10000).
+* `ETHEREUM_PARALLEL_BLOCK_RANGES` - Maximum number of parallel `eth_getLogs` calls to make when scanning logs for a subgraph. Defaults to 100.
## Running mapping handlers
* `GRAPH_EVENT_HANDLER_TIMEOUT`: amount of time an event handler is allowed
