Fix outdated version number

[ilarischeinin]

As @cderv mentions here, an odd thing has happened with purrr's version numbers.

The current CRAN version is 0.2.5, whereas the master branch on GitHub is 0.2.4.9000. The fixes that were implemented between 0.2.4 and 0.2.4.9000 are not included in the 0.2.5 release. That one was a "maintenance release following the release of dplyr 0.7.5", which I guess came in though some other pipeline than the "normal" GitHub path.

I noticed this as I ran into the bug reported in #429 (parameter .id is ignored in imap_dfr()), for which a fix was merged on Feb 5 in #454. However, while this fix is on the current master branch (0.2.4.9000), it is not included in CRAN's 0.2.5.

The result is that I cannot make my package depend on the fixed version, as 0.2.5 > 0.2.4.9000.

This PR hence bumps the version number on GitHub from 0.2.4.9000 to 0.2.5.9000. Then it is possible to make another package depend on purrr 0.2.5.9000, which does include the needed fix.

[stufield]

This issue is also relevant to #417, fixes between 0.2.4 and 0.2.4.9000 are not included in the 0.2.5 release, the maintenance of object structures being one of them. Thus my confusion in the comments of the issue about the ordering of the release versions.

[lionel-]

Thanks!