According to the CLA signing instructions, the date of signature must be
expressed in the following form:
> `<date>`: current date in the form `YYYY-MM-DD`
However, the date was wrongly expressed as "9-2-2015". That date not
only was following an incorrect format, but also it was ambiguous,
because it was not clear if the format was following M-D-YYYY or
D-M-YYYY (the latter one being the case).
This fixes the format, so it now fits the required one.
Closes#25665
Luis González
2d0621da05