Include the entirety of vendor folder in .gitignore (#15046)

The 'go mod vendor' command generates a directory called 
'vendor' in the main module's root directory, which includes 
the required packages to support builds. Therefore, we can 
include the 'vendor' directory in .gitignore completely, 
regardless of any file extension.

.gitignore

@@ -9,8 +9,7 @@ site/
 /.idea/
 /Minio.iml
 **/access.log
-vendor/**/*.js
-vendor/**/*.json
+vendor/
 .DS_Store
 *.syso
 coverage.txt