Make update-version also update the doxy.conf file

doxy.conf has PROJECT_NUMBER, which it uses to display the version
(and yes, that *is* an odd name). With this patch that number gets
updated when we update a version too though.

Signed-off-by: Daniel Wittenberg <dwittenberg2008@gmail.com>
Signed-off-by: Andreas Ericsson <ae@op5.se>
specfile: BuildRequires: gperf

Otherwise we can't build the perfect hash tables used when we parse
checkresults from one of our workers.

Signed-off-by: Daniel Wittenberg <dwittenberg2008@gmail.com>
Signed-off-by: Andreas Ericsson <ae@op5.se>