Minor README Grammar Correction (allegro#193)

README.md

@@ -1,7 +1,7 @@
 # BigCache [![Build Status](https://github.com/allegro/bigcache/workflows/build.yml/badge.svg)](https:/github.com.org/allegro/bigcache/workflows/build.yml) [![Coverage Status](https://coveralls.io/repos/github/allegro/bigcache/badge.svg?branch=master)](https://coveralls.io/github/allegro/bigcache?branch=master) [![GoDoc](https://godoc.org/github.com/allegro/bigcache?status.svg)](https://godoc.org/github.com/allegro/bigcache) [![Go Report Card](https://goreportcard.com/badge/github.com/allegro/bigcache)](https://goreportcard.com/report/github.com/allegro/bigcache)
 
 Fast, concurrent, evicting in-memory cache written to keep big number of entries without impact on performance.
-BigCache keeps entries on heap but omits GC for them. To achieve that operations on byte slices take place,
+BigCache keeps entries on heap but omits GC for them. To achieve that, operations on byte slices take place,
 therefore entries (de)serialization in front of the cache will be needed in most use cases.
 
 Requires Go 1.12 or newer.