meson: Bump version to 1.8.0
meson: Bump version to 1.8.0

It was not updated during the last version bump

cisco/openh264,shihuade/openh264,GuangweiWang/openh264,ruil2/openh264,mstorsjo/openh264,mstorsjo/openh264,ruil2/openh264,shihuade/openh264,cisco/openh264,shihuade/openh264,GuangweiWang/openh264,shihuade/openh264,ruil2/openh264,cisco/openh264,mstorsjo/openh264,cisco/openh264,mstorsjo/openh264,ruil2/openh264,GuangweiWang/openh264,mstorsjo/openh264,shihuade/openh264,cisco/openh264,GuangweiWang/openh264,ruil2/openh264,cisco/openh264,GuangweiWang/openh264,GuangweiWang/openh264,shihuade/openh264,mstorsjo/openh264,cisco/openh264,ruil2/openh264,shihuade/openh264,mstorsjo/openh264,ruil2/openh264,GuangweiWang/openh264