Update installation.md

Gazelle-Security-Suite/installation.md

@@ -272,3 +272,4 @@ If you import an existing CA, do not use a CA chained to an issuer publicly trus
 | **tls\_simulator\_address**                           | Manual SSL/TLS simulators address (host / IP). Only displayed if tls\_automatic\_simulator\_address\_enabled is set to false.                                                                                                        | null                                                                                                              |
 | **xua\_mode\_enabled**                                | Enable/disable XUA assertions validator.                                                                                                                                                                                             | true                                                                                                              |
 | **xmldsig_core_schema_location** | URL to the XML schema for verifying ds:Signature element |https://gazelle.ihe.net/XSD/IHE/XUA/xmldsig-core-schema.xsd |
+| **http_max_content_size** | The maximum size of http content that can be supported by the http proxy (the size is in MB) |16 |