[JENKINS-68887] CssSyntaxError when linting war module on Windows (#6744)

.gitattributes

@@ -15,7 +15,8 @@
 *.json          text
 *.jelly         text
 *.jellytag      text
-*.less          text
+# JENKINS-68887: postcss-less fails to properly parse .less files with Windows line breaks
+*.less          text eol=lf
 *.properties    text
 *.rb            text
 *.sh            text