ci: make sure liblzma is installed #1109

Job	Run time
html5lib-tests	53s
jruby-head	59s
ruby-head (ubuntu, enable)	45s
ruby-head-valgrind (disable)	5m 59s
ruby-head (ubuntu, disable)	49s
truffleruby-head (--disable-system-libraries --disable-static)	3m 7s
ruby-head (windows, enable)	3m 18s
truffleruby-head (--disable-system-libraries --enable-static)	3m 8s
ruby-head (windows, disable)	3m 59s
truffleruby-head (--enable-system-libraries)	2m 44s
ruby-head (macos, enable)	28s
xmlsoft-head (ubuntu)	1m 47s
ruby-head (macos, disable)	41s
xmlsoft-head (windows)	8m 56s
xmlsoft-head (macos)	2m 1s
xmlsoft-head-valgrind	6m 47s
	46m 21s

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