feat: add logic to convert severity string to uppercase (#744)

Author: Yoshi Yamaguchi

Diff for: google/cloud/logging_v2/entries.py

@@ -229,7 +229,10 @@ def to_api_repr(self):
         if self.insert_id is not None:
             info["insertId"] = self.insert_id
         if self.severity is not None:
-            info["severity"] = self.severity
+            if isinstance(self.severity, str):
+                info["severity"] = self.severity.upper()
+            else:
+                info["severity"] = self.severity
         if self.http_request is not None:
             info["httpRequest"] = self.http_request
         if self.timestamp is not None:

Diff for: google/cloud/logging_v2/logger.py

@@ -141,7 +141,7 @@ def _do_log(self, client, _entry_class, payload=None, **kw):
         kw["resource"] = kw.pop("resource", self.default_resource)
 
         severity = kw.get("severity", None)
-        if isinstance(severity, str) and not severity.isupper():
+        if isinstance(severity, str):
             # convert severity to upper case, as expected by enum definition
             kw["severity"] = severity.upper()