update to protobuf to 5.28.0, fix test and remove mypy ignore

src/extract_otp_secrets.py

@@ -592,7 +592,7 @@ def convert_img_to_otp_urls(filename: str, args: Args) -> OtpUrls:
                 stdin = sys.stdin.buffer.read()
             except AttributeError:
                 # Workaround for pytest, since pytest cannot monkeypatch sys.stdin.buffer
-                stdin = sys.stdin.read()  # type: ignore # Workaround for pytest fixtures
+                stdin = sys.stdin.read()
             if not stdin:
                 log_warn("stdin is empty")
             try:

src/protobuf_generated_python/google_auth_pb2.py

@@ -2,7 +2,7 @@
 # Generated by the protocol buffer compiler.  DO NOT EDIT!
 # NO CHECKED-IN PROTOBUF GENCODE
 # source: google_auth.proto
-# Protobuf Python Version: 5.27.2
+# Protobuf Python Version: 5.28.0
 """Generated protocol buffer code."""
 from google.protobuf import descriptor as _descriptor
 from google.protobuf import descriptor_pool as _descriptor_pool
@@ -12,8 +12,8 @@ from google.protobuf.internal import builder as _builder
 _runtime_version.ValidateProtobufRuntimeVersion(
     _runtime_version.Domain.PUBLIC,
     5,
-    27,
-    2,
+    28,
+    0,
     '',
     'google_auth.proto'
 )