Reminder: Please add "Since" version info also to cmake macros and arguments

[Friedrich W. H. Kossebau]

Hi,

please remember to add some info about for which version of KF5 or ECM a new 
cmake macro or argument was added (or changed behaviour).

So people with a newer version of ECM/KF5 installed on their system, but 
working on a software using ECM/KF5 with lower minimal version requirements 
can quickly see whether some macro or parameter can be used or will break 
things for people with the minimal version installed.

As the API dox syntax for cmake macro seems to not have something like a 
"@since" tag, at least in one example I know instead the Since tag is simply 
written verbatim in the text, see
	http://api.kde.org/ecm/module/ECMGenerateHeaders.html?highlight=Since
	https://quickgit.kde.org/?p=extra-cmake-modules.git&a=blob&f=modules%2FECMGenerateHeaders.cmake

Or is there some better way now to tag the version where things appeared?


Example:
I just wanted to know since which KF5 version the cmake macro 
"kcoreaddons_add_plugin" exists, working on software with a KF5 5.7 minimal 
version requirement.
Having to hunt the version down in the git repo is not perfect ;) (and no, is 
too new to be used, added in 5.10)


I am happy to fix at least KF5CoreAddonsMacros.cmake now that I came across 
it, appending the Since behind the example, if that is the current syntax?

# Example:
#   kcoreaddons_add_plugin(kdeconnect_share JSON kdeconnect_share.json SOURCES 
${kdeconnect_share_SRCS})
#
# Since 5.10.0

Cheers
Friedrich