Goocanvas 3.0 is needed to build and contribute to Akira, and as far as I know, it is now maintained by a member or Akira development team (https://fosstodon.org/@akiraux/105575273313648788).
Link:
https://download.gnome.org/sources/goocanvas/3.0/goocanvas-3.0.0.tar.xz
Changes:
GooCanvas 3.0.0 (Jan 16 2021)
o Allow customize each corner radius for rectangle shape
o Bump gettext version
o Rotate Skew demo
o Let goo_canvas_pointer_grab take NULL
o Change the ABI from goocanvas-2.0 to goocanvas-3.0.