Update liblouis to 3.18.0 (#12526)
New braille tables: Bulgarian grade 1, Burmese grade 1, Burmese grade 2, Kazakh grade 1, Khmer grade 1, Northern Kurdish grade 0, Sepedi grade 1, Sepedi grade 2, Sesotho grade 1, Sesotho grade 2, Setswana grade 1, Setswana grade 2, Tatar grade 1, Vietnamese grade 0, Vietnamese grade 2, Southern Vietnamese grade 1, Xhosa grade 1, Xhosa grade 2, Yakut grade 1, Zulu grade 1, Zulu grade 2
