chore: sync infra OpenAPI specs

Author: dobrac

spec/openapi.infra.yaml

@@ -388,6 +388,7 @@ components:
         - cpuUsedPct
         - memUsed
         - memTotal
+        - memCache
         - diskUsed
         - diskTotal
       properties:
@@ -416,6 +417,10 @@ components:
           type: integer
           format: int64
           description: Total memory in bytes
+        memCache:
+          type: integer
+          format: int64
+          description: Cached memory (page cache) in bytes
         diskUsed:
           type: integer
           format: int64