Revert "overview, readme: update ETL wording (#677)"

This reverts commit 6a754d9.

Author: QueenyJin

README.md

@@ -188,7 +188,7 @@ TiDB (The pronunciation is: /'taɪdiːbi:/ tai-D-B, etymology: titanium) is an o
 
     TiDB is designed to work in the cloud -- public, private, or hybrid -- making deployment, provisioning, and maintenance drop-dead simple.
 
-- __Minimal ETL__
+- __Minimize ETL__
 
     ETL (Extract, Transform and Load) is no longer necessary with TiDB's hybrid OLTP/OLAP architecture, enabling you to create new values for your users, easier and faster.
 

overview.md

@@ -24,7 +24,7 @@ TiDB (The pronunciation is: /'taɪdiːbi:/ tai-D-B, etymology: titanium) is an o
 
     TiDB is designed to work in the cloud -- public, private, or hybrid -- making deployment, provisioning, and maintenance drop-dead simple.
 
-- __Minimal ETL__
+- __Minimize ETL__
 
     ETL (Extract, Transform and Load) is no longer necessary with TiDB's hybrid OLTP/OLAP architecture, enabling you to create new values for your users, easier and faster.