fix: always expand Env for CORS configuratio

cmd/tank/config.go

@@ -81,9 +81,7 @@ func (c *Config) ExpandEnv() {
 		c.Auth.ExpandEnv()
 	}
 	c.Web.AccessLogs = os.ExpandEnv(c.Web.AccessLogs)
-	if c.Web.Cors != nil {
-		c.Web.Cors.ExpandEnv()
-	}
+	c.Web.Cors.ExpandEnv()
 }
 
 func ReadConfig(configfile string) (conf *Config, err error) {