Fix a typo

README.md

@@ -22,7 +22,7 @@ To start learning about Kokkos:
 
 - [API reference](https://kokkos.org/kokkos-core-wiki/): organized by category, i.e., [core](https://kokkos.org/kokkos-core-wiki/API/core-index.html), [algorithms](https://kokkos.org/kokkos-core-wiki/API/algorithms-index.html) and [containers](https://kokkos.org/kokkos-core-wiki/API/containers-index.html) or, if you prefer, in [alphabetical order](https://kokkos.org/kokkos-core-wiki/API/alphabetical.html).
 
-- [Use cases and Examples](https://kokkos.org/kokkos-core-wiki/usecases.html): a series of examples ranging from how to use Kokkos with MPI to Fortran interoperability.
+- [Use cases and Examples](https://kokkos.org/kokkos-core-wiki/usecases.html): a serie of examples ranging from how to use Kokkos with MPI to Fortran interoperability.
 
 ## Obtaining Kokkos