[LyX/2.3.x] Prepare for 2.3.5

[José Abílio Matos]

On Monday, 1 June 2020 18.47.30 WEST Richard Kimberly Heck wrote:
>  # Use ISO format only. The frontend needs to parse this
> -AC_SUBST(LYX_DATE, ["2020-01-26"])
> +AC_SUBST(LYX_DATE, ["2020-06-21"])

Hi Riki,
  I am curious about this. Did you apply a permutation to get the new date. 
;-) There are the same digits but in a different order. :-)

Thank you for the new release.
-- 
José Abílio