tls: change var to const

PR-URL: #22219
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>
Reviewed-By: Gus Caplan <me@gus.host>
Reviewed-By: Jon Moss <me@jonathanmoss.me>

lib/internal/tls.js

@@ -3,13 +3,13 @@
 // Example:
 // C=US\nST=CA\nL=SF\nO=Joyent\nOU=Node.js\nCN=ca1\nemailAddress=ry@clouds.org
 function parseCertString(s) {
-  var out = Object.create(null);
-  var parts = s.split('\n');
+  const out = Object.create(null);
+  const parts = s.split('\n');
   for (var i = 0, len = parts.length; i < len; i++) {
-    var sepIndex = parts[i].indexOf('=');
+    const sepIndex = parts[i].indexOf('=');
     if (sepIndex > 0) {
-      var key = parts[i].slice(0, sepIndex);
-      var value = parts[i].slice(sepIndex + 1);
+      const key = parts[i].slice(0, sepIndex);
+      const value = parts[i].slice(sepIndex + 1);
       if (key in out) {
         if (!Array.isArray(out[key])) {
           out[key] = [out[key]];