clean up: deprecation warnings

```
warning: use of deprecated item 'bincode::config': please use `options()` instead
--> src/new_index/schema.rs:1421:9
|
1421 | bincode::config()
| ^^^^^^^^^^^^^^^
|
= note: `#[warn(deprecated)]` on by default

warning: use of deprecated item 'bincode::config': please use `options()` instead
--> src/new_index/schema.rs:1429:18
|
1429 | key: bincode::config().big_endian().serialize(&self.key).unwrap(),
| ^^^^^^^^^^^^^^^

warning: use of deprecated item 'bincode::config': please use `options()` instead
--> src/new_index/schema.rs:1435:19
|
1435 | let key = bincode::config()
| ^^^^^^^^^^^^^^^

warning: 3 warnings emitted

warning: use of deprecated item 'bincode::config': please use `options()` instead
--> src/bin/popular-scripts.rs:26:35
|
26 | let entry: TxHistoryKey = bincode::config()
| ^^^^^^^^^^^^^^^
|
= note: `#[warn(deprecated)]` on by default

```