[Infra) fix relative link in README.md.

Author: reegeek

README.md

@@ -42,15 +42,15 @@ You can also improve performance by using struct for Where predicate and select
 
 ## Performances
 
-Benchmark are in [here](src\StructLinq.Benchmark).
+Benchmark are in [here](src/StructLinq.Benchmark).
 For example on following linq sequence:
  ```csharp
     array
       .Where(x => (x & 1) == 0)
       .Select(x => x * 2)
       .Sum();
  ```
- [Benchmark](src\StructLinq.Benchmark\ArrayWhereSelectSum.cs) results are:
+ [Benchmark](src/StructLinq.Benchmark/ArrayWhereSelectSum.cs) results are:
 
  ``` ini