tools: ensure consistent perms of signed release files

Fixes: nodejs/build#1904

PR-URL: #29350
Reviewed-By: Myles Borins <myles.borins@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Beth Griggs <Bethany.Griggs@uk.ibm.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>

tools/release.sh

@@ -144,6 +144,7 @@ function sign {
 
     if [ "X${yorn}" == "Xy" ]; then
       scp ${customsshkey} ${tmpdir}/${shafile} ${tmpdir}/${shafile}.asc ${tmpdir}/${shafile}.sig ${webuser}@${webhost}:${shadir}/
+      ssh ${customsshkey} ${webuser}@${webhost} chmod 644 ${shadir}/${shafile}.asc ${shadir}/${shafile}.sig
       break
     fi
   done