Grammar fix (#6149)

Scheduler description is grammatically error. Replaced "an unifrom" with "a uniform"

Author: spreddy2714

README.md

@@ -193,7 +193,7 @@ Typically, you can move computations or blocking IO to some other thread via `su
 
 ### Schedulers
 
-RxJava operators don't work with `Thread`s or `ExecutorService`s directly but with so called `Scheduler`s that abstract away sources of concurrency behind an uniform API. RxJava 2 features several standard schedulers accessible via `Schedulers` utility class. 
+RxJava operators don't work with `Thread`s or `ExecutorService`s directly but with so called `Scheduler`s that abstract away sources of concurrency behind a uniform API. RxJava 2 features several standard schedulers accessible via `Schedulers` utility class. 
 
 - `Schedulers.computation()`: Run computation intensive work on a fixed number of dedicated threads in the background. Most asynchronous operator use this as their default `Scheduler`.
 - `Schedulers.io()`: Run I/O-like or blocking operations on a dynamically changing set of threads.