Failed to upgrade the package through pip

I'm running Ubuntu 16.04 and I have the 3.20.0 version of pygobject installed as of now.

pip shows that there's an upgrade to 3.27.1, but when I attempt it, I get the following error message:

...
building 'gi._gi_cairo' extension
    x86_64-linux-gnu-gcc -pthread -DNDEBUG -g -fwrapv -O2 -Wall -Wstrict-prototypes -g -fstack-protector-strong -Wformat -Werror=format-security -Wdate-time -D_FORTIFY_SOURCE=2 -fPIC -DHAVE_CONFIG_H -I/tmp/pip-build-i1etm5v5/pygobject -I/tmp/pip-build-i1etm5v5/pygobject/gi -I/usr/include/glib-2.0 -I/usr/lib/x86_64-linux-gnu/glib-2.0/include -I/usr/include/glib-2.0 -I/usr/lib/x86_64-linux-gnu/glib-2.0/include -I/usr/include/gobject-introspection-1.0 -I/usr/include/glib-2.0 -I/usr/lib/x86_64-linux-gnu/glib-2.0/include -I/usr/include/cairo -I/usr/include/glib-2.0 -I/usr/lib/x86_64-linux-gnu/glib-2.0/include -I/usr/include/pixman-1 -I/usr/include/freetype2 -I/usr/include/libpng12 -I/usr/include/cairo -I/usr/include/pixman-1 -I/usr/include/freetype2 -I/usr/include/libpng12 -I/usr/include/glib-2.0 -I/usr/lib/x86_64-linux-gnu/glib-2.0/include -I/usr/include/pycairo -I/usr/include/python3.5m -c gi/pygi-foreign-cairo.c -o build/temp.linux-x86_64-3.5/gi/pygi-foreign-cairo.o
    gi/pygi-foreign-cairo.c:31:22: fatal error: py3cairo.h: No such file or directory
    compilation terminated.

Full log available here.

What's the cause?