Update administration-pulsar-manager.md (#728)

Getting error ;

gzip: stdin: not in gzip format
tar: Child returned status 1
tar: Error is not recoverable: exiting now

because the compression is not gzip.

pulsar-manager.tar: POSIX tar archive

versioned_docs/version-3.1.x/administration-pulsar-manager.md

@@ -134,7 +134,7 @@ When using binary packages for direct deployment, you can follow these steps.
 
   ```bash
   	cd pulsar-manager
-  	tar -zxvf pulsar-manager.tar
+  	tar -xvf pulsar-manager.tar
   	cd pulsar-manager
   	cp -r ../dist ui
   ```