CI: Fix listing

Author: Flamefire

.github/workflows/ci.yml

@@ -79,7 +79,7 @@ jobs:
         run: |
             sudo apt-get install -y doxygen
             B2_TARGETS=libs/$SELF/doc ci/build.sh
-            find libs/$SELF/doc/html
+            find $BOOST_ROOT/libs/$SELF/doc/html
 
   posix:
     defaults: