I want to create a pin like that (not round ) i use os ubuntu
Assuming you want pcb view and can use an svg editor such as Inkscape, a suitable footprint to copy from is available in the Sparkfun ICL3232 (searching for ICL3232 in the parts bin will find it). Since the base pin is a circle with the wide section overlaying it you should be able to copy/ paste just the wider pad you want in to your current svg. There may also be a 28 pin part somewhere with this footprint, I just don’t know where it is (if it exists).
A very reasonable question.
This should be in core library !
Maybe a suggestion for next version (whenever release will be)?
No need to wait for a code update. If someone makes such a part and submits it for part update then in due course (independent of a code release) it will appear in core parts. The key point here is “if someone makes”, we are someone. If we want things in Fritzing (including code changes) we need to be willing to provide the work to make them happen.