Backport PR pandas-dev#34845: DOC: 1.0.5 release date

Author: simonjayhawkins

doc/source/whatsnew/v1.0.5.rst

@@ -1,7 +1,7 @@
 
 .. _whatsnew_105:
 
-What's new in 1.0.5 (June XX, 2020)
+What's new in 1.0.5 (June 17, 2020)
 -----------------------------------
 
 These are the changes in pandas 1.0.5. See :ref:`release` for a full changelog