Add missing comma in stacks.json

Signed-off-by: Mario Loriedo <mloriedo@redhat.com>

Author: l0rd

ide/che-core-ide-stacks/src/main/resources/stacks.json

@@ -2275,7 +2275,7 @@
                 "memoryLimitBytes": "2147483648"
               },
               "agents": [
-	        "org.eclipse.che.exec"
+                "org.eclipse.che.exec",
                 "org.eclipse.che.terminal",
                 "org.eclipse.che.ws-agent",
                 "org.eclipse.che.ssh"