Updating dependencies (#9139)

vendor/github.com/go-sql-driver/mysql/README.md

@@ -40,7 +40,7 @@ A MySQL-Driver for Go's [database/sql](https://golang.org/pkg/database/sql/) pac
   * Optional placeholder interpolation
 
 ## Requirements
-  * Go 1.7 or higher. We aim to support the 3 latest versions of Go.
+  * Go 1.8 or higher. We aim to support the 3 latest versions of Go.
   * MySQL (4.1+), MariaDB, Percona Server, Google CloudSQL or Sphinx (2.2.3+)
 
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