docs: fix the docker cli of running clair in README.md

Signed-off-by: Lei Jitang <leijitang@huawei.com>

README.md

@@ -58,7 +58,7 @@ The easiest way to get an instance of Clair running is to simply pull down the l
 $ mkdir $HOME/clair_config
 $ curl -L https://raw.githubusercontent.com/coreos/clair/config.example.yaml -o $HOME/clair_config/config.yaml
 $ $EDITOR $HOME/clair_config/config.yaml # Add the URI for your postgres database
-$ docker run quay.io/coreos/clair -p 6060-6061:6060-6061 -v $HOME/clair_config:/config -config=config.yaml
+$ docker run -p 6060-6061:6060-6061 -v $HOME/clair_config:/config quay.io/coreos/clair -config=/config/config.yaml
 ```
 
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