electrs indexing crashes with 137

I'm able to run electrs but blockstream/electrs does not make it very far on the initial sync. The process kills itself with no explanation after `DEBUG - writing 1421479 rows to RocksDB { path: "./db/mainnet/newindex/txstore" }, flush=Disable`

Any pointers would be greatly appreciated!

```
Config { log: StdErrLog { verbosity: Trace, quiet: false, show_level: true, timestamp: Off, modules: [], writer: "stderr", color_choice: Never }, network_type: Bitcoin, db_path: "./db/mainnet", daemon_dir: "/home/bitcoin/.bitcoin", blocks_dir: "/home/bitcoin/.bitcoin/blocks", daemon_rpc_addr: 127.0.0.1:8332, cookie: Some("bitcoin:bitcoinpass"), electrum_rpc_addr: 127.0.0.1:50001, http_addr: 127.0.0.1:3000, http_socket_file: None, monitoring_addr: 127.0.0.1:4224, jsonrpc_import: false, light_mode: false, address_search: false, index_unspendables: false, cors: None, precache_scripts: None, utxos_limit: 500, electrum_txs_limit: 500, electrum_banner: "Welcome to electrs-esplora 0.4.1" }
DEBUG - Server listening on 127.0.0.1:4224
DEBUG - Running accept thread
INFO - NetworkInfo { version: 220000, subversion: "/Satoshi:22.0.0/", relayfee: 1e-5 }
INFO - BlockchainInfo { chain: "main", blocks: 752786, headers: 752786, bestblockhash: "0000000000000000000442240f6c03af907af5beb1571be3b9c96faa9f91bc2e", pruned: false, verificationprogress: 0.9999988, initialblockdownload: Some(false) }
DEBUG - opening DB at "./db/mainnet/newindex/txstore"
DEBUG - 0 blocks were added
DEBUG - opening DB at "./db/mainnet/newindex/history"
DEBUG - 0 blocks were indexed
DEBUG - opening DB at "./db/mainnet/newindex/cache"
DEBUG - downloading all block headers up to 0000000000000000000442240f6c03af907af5beb1571be3b9c96faa9f91bc2e
TRACE - downloading 100000 block headers
TRACE - downloading 100000 block headers
TRACE - downloading 100000 block headers
TRACE - downloading 100000 block headers
TRACE - downloading 100000 block headers
TRACE - downloading 100000 block headers
TRACE - downloading 100000 block headers
TRACE - downloading 52787 block headers
INFO - hash=0000000000000000000442240f6c03af907af5beb1571be3b9c96faa9f91bc2e height=752786 @ 2022-09-05T21:12:22Z (752787 left to index)
DEBUG - adding transactions from 752787 blocks using BlkFiles
DEBUG - listing block files at "/home/bitcoin/.bitcoin/blocks/blk*.dat"
TRACE - reading "/home/bitcoin/.bitcoin/blocks/blk00000.dat"
TRACE - parsing 134217315 bytes
TRACE - reading "/home/bitcoin/.bitcoin/blocks/blk00001.dat"
TRACE - reading "/home/bitcoin/.bitcoin/blocks/blk00002.dat"
TRACE - parsing 134217222 bytes
TRACE - reading "/home/bitcoin/.bitcoin/blocks/blk00003.dat"
TRACE - fetched 119964 blocks
TRACE - parsing 134172167 bytes
TRACE - fetched 11270 blocks
TRACE - reading "/home/bitcoin/.bitcoin/blocks/blk00004.dat"
TRACE - parsing 134206510 bytes
TRACE - fetched 5694 blocks
TRACE - reading "/home/bitcoin/.bitcoin/blocks/blk00005.dat"
TRACE - parsing 134210691 bytes
TRACE - reading "/home/bitcoin/.bitcoin/blocks/blk00006.dat"
DEBUG - writing 2003707 rows to RocksDB { path: "./db/mainnet/newindex/txstore" }, flush=Disable
TRACE - parsing 134192813 bytes
TRACE - reading "/home/bitcoin/.bitcoin/blocks/blk00007.dat"
TRACE - fetched 5719 blocks
DEBUG - writing 1421479 rows to RocksDB { path: "./db/mainnet/newindex/txstore" }, flush=Disable
./scripts/run.sh: line 19: 21834 Killed $CARGO run --release "$@" 2>> "$LOG"
```