python/PyPDF2: Build for python3 too.

Signed-off-by: Andrew Clemons <andrew.clemons@gmail.com>

Signed-off-by: Willy Sudiarto Raharjo <willysr@slackbuilds.org>

python/PyPDF2/PyPDF2.SlackBuild

@@ -84,6 +84,7 @@ find -L . \
   -o -perm 440 -o -perm 400 \) -exec chmod 644 {} \;
 
 python setup.py install --root=$PKG
+python3 setup.py install --root=$PKG
 
 find $PKG -print0 | xargs -0 file | grep -e "executable" -e "shared object" | grep ELF \
   | cut -f 1 -d : | xargs strip --strip-unneeded 2> /dev/null || true