Update to strophe 1.2.12. Updates #751 and #753

docs/CHANGES.md

 # Changelog
 
 ## 2.0.5
+- #743, #751, #753 Update to Strophe 1.2.12. SASL-EXTERNAL now has reduced priority, so it won't
+  be prioritized above other auth mechanisms. [jcbrand]
 - #755: create composer.json to add this project in packagist.org [fabiomontefuscolo]
 - Bugfix. Cancel button shown while registration form is being fetched wasn't working
   properly. [jcbrand]

package.json

@@ -57,7 +57,7 @@
     "po2json": "^0.4.4",
     "requirejs": "2.3.2",
     "requirejs-undertemplate": "~0.0.4",
-    "strophe.js": "1.2.11",
+    "strophe.js": "1.2.12",
     "snyk": "^1.21.2",
     "strophejs-plugins": "0.0.7",
     "text": "requirejs/text#2.0.15",