fix: TeX Live package is lm, not lmodern

The previous commit added `soft lmodern` to DEPENDS.txt, but tlmgr
fails with "package lmodern not present in repository". The TeX Live
package that provides lmodern.sty is named `lm`.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: yegor256

DEPENDS.txt

@@ -7,7 +7,7 @@ soft ffcode
 soft href-ul
 soft hypdoc
 soft l3build
-soft lmodern
+soft lm
 soft microtype
 soft newtx
 soft pgfopts