feat: optional stdout decoding (#351)

Do not decode stdout if the bytes cannot be represented as UTF-8.

Refs: #350

Co-authored-by: Jessica Tegner <jessica.tegner@outlook.com>

pypandoc/__init__.py

@@ -450,7 +450,8 @@ def _convert_input(source, format, input_type, to, extra_args=(),
         raise RuntimeError('Pandoc died with exitcode "%s" during conversion.' % (p.returncode))
 
     try:
-        stdout = stdout.decode('utf-8')
+        if not (to in ["odt", "docx", "epub", "epub3", "pdf"] and outputfile == "-"):
+            stdout = stdout.decode('utf-8')
     except UnicodeDecodeError:
         # this shouldn't happen: pandoc more or less guarantees that the output is utf-8!
         raise RuntimeError('Pandoc output was not utf-8.')