chore: bump version to 0.2.1 and fix clippy warnings

- Fix needless reference operators in expressions.rs:719 and 737
- Bump version from 0.2.0 to 0.2.1 for PyPI release

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: elyase

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "maturin"
 
 [project]
 name = "polars_u256_plugin"
-version = "0.2.0"
+version = "0.2.1"
 description = "Polars plugin for 256-bit U256 and signed I256 (two's complement) integers backed by ruint"
 readme = "README.md"
 requires-python = ">=3.9"

src/expressions.rs

@@ -716,7 +716,7 @@ pub fn u256_min(inputs: &[Series]) -> PolarsResult<Series> {
         let mut arr=[0u8;32]; arr.copy_from_slice(v);
         match &mut minv {
             None => minv = Some(arr),
-            Some(m) => { if &arr[..] < &m[..] { *m = arr; } }
+            Some(m) => { if arr[..] < m[..] { *m = arr; } }
         }
     }
     let out = match minv { Some(x) => Series::new(s0.name().clone(), [Some(x.to_vec())]), None => Series::new(s0.name().clone(), [Option::<Vec<u8>>::None]) };
@@ -734,7 +734,7 @@ pub fn u256_max(inputs: &[Series]) -> PolarsResult<Series> {
         let mut arr=[0u8;32]; arr.copy_from_slice(v);
         match &mut maxv {
             None => maxv = Some(arr),
-            Some(m) => { if &arr[..] > &m[..] { *m = arr; } }
+            Some(m) => { if arr[..] > m[..] { *m = arr; } }
         }
     }
     let out = match maxv { Some(x) => Series::new(s0.name().clone(), [Some(x.to_vec())]), None => Series::new(s0.name().clone(), [Option::<Vec<u8>>::None]) };