Indicate likely minimum version.

I started this a couple of years ago and so was using a 1.3ish
release. Looking through the repository, it looks like the APIs
I'm using are stable since then.

Author: detrout

pandas/io/excel/_odfreader.py

@@ -16,7 +16,7 @@ def __init__(self, filepath_or_buffer):
             from odf.opendocument import load as document_load
             from odf.table import Table
         except ImportError:
-            raise ImportError("Install odfpy for OpenDocument support")
+            raise ImportError("Install odfpy >= 1.3 for OpenDocument support")
 
         self.filepath_or_buffer = filepath_or_buffer
         self.document = document_load(filepath_or_buffer)