fix saml env

docs/system-admin-guide/authentication/saml/README.md

@@ -474,7 +474,7 @@ OPENPROJECT_SAML_SAML_ASSERTION__CONSUMER__SERVICE__URL="https://<Your OpenProje
 OPENPROJECT_SAML_SAML_SSO__TARGET__URL="https://<Your ADFS hostname>/adfs/ls"
 OPENPROJECT_SAML_SAML_SLO__TARGET__URL="https://<Your ADFS hostname>/adfs/ls/?wa=wsignout1.0"
 OPENPROJECT_SAML_SAML_ISSUER="https://<Your OpenProject hostname>"
-OPENPROJECT_SAML_SAML_IDP_CERT="<The output of the awk command above>"
+OPENPROJECT_SAML_SAML_IDP__CERT="<The output of the awk command above>"
 ```
 
 
@@ -533,7 +533,8 @@ OPENPROJECT_SAML_SAML_ASSERTION__CONSUMER__SERVICE__URL="https://<Your OpenProje
 OPENPROJECT_SAML_SAML_SSO__TARGET__URL="https://<Your Keycloak hostname>/realms/<Keycloak REALM>/protocol/saml"
 OPENPROJECT_SAML_SAML_SLO__TARGET__URL="https://<Your Keycloak hostname>/realms/<Keycloak RELAM>/protocol/saml"
 OPENPROJECT_SAML_SAML_ISSUER="https://<Your OpenProject hostname>"
-OPENPROJECT_SAML_SAML_IDP_CERT="<The certificate base64 copied from the metadata XML>"
+OPENPROJECT_SAML_SAML_IDP__SSO__SERVICE__URL="https://<Your Keycloak hostname>/realms/<Keycloak RELAM>/protocol/saml"
+OPENPROJECT_SAML_SAML_IDP__CERT="<The certificate base64 copied from the metadata XML>"
 ```
 
 If you're unsure what the realm value is, go to the menu "Realm settings" and click on "Endpoints -> SAML 2.0 Identity Provider Metadata". This will include URLs for the `SingleSignOnSerivce` and `SingleLogoutService`.