feat(Firewall): New fields for show_system_resources (#544)

* linter passed, tests passed for enhancement

* Update firewall.py

fixing format issue

---------

Co-authored-by: Keith Campbell <keith@keiths-mbp.mynetworksettings.com>

panos/firewall.py

@@ -426,24 +426,27 @@ def show_system_resources(self):
         result = self.xapi.xml_root()
         if self._version_info >= (9, 0, 0):
             regex = re.compile(
-                r"load average: ([\d\.]+).*? ([\d\.]+) id,.*KiB Mem :\s+(\d+) total,.*? (\d+) free",
+                r"load average: ([\d\.]+).*? ([\d\.]+) id,.*KiB Mem :"
+                r"\s+(\d+) total,.*? (\d+) free.*? (\d+) used,"
+                r".*? (\d+) buff/cache",
                 re.DOTALL,
             )
         else:
             regex = re.compile(
-                r"load average: ([\d.]+).* ([\d.]+)%id.*Mem:.*?([\d.]+)k total.*?([\d]+)k free",
+                r"load average: ([\d.]+).* ([\d.]+)%id.*"
+                r"Mem:.*?([\d.]+)k total.*?"
+                r"([\d]+)k free.*?([\d]+)k used.*?([\d]+)k buff/cache",
                 re.DOTALL,
             )
         match = regex.search(result)
         if match:
-            """
-            return cpu, mem_free, load
-            """
             return {
                 "load": Decimal(match.group(1)),
                 "cpu": 100 - Decimal(match.group(2)),
                 "mem_total": int(match.group(3)),
                 "mem_free": int(match.group(4)),
+                "mem_used": int(match.group(5)),
+                "mem_buffer": int(match.group(6)),
             }
         else:
             raise err.PanDeviceError(