Allow to pass integrity & async attribute to extra js

site/content/docs/4.3/examples/checkout/index.html

@@ -4,7 +4,7 @@ title: Checkout example
 extra_css:
   - "form-validation.css"
 extra_js:
-  - "form-validation.js"
+  - src: "form-validation.js"
 body_class: "bg-light"
 ---
 

site/content/docs/4.3/examples/dashboard/index.html

@@ -4,9 +4,11 @@ title: Dashboard Template
 extra_css:
   - "dashboard.css"
 extra_js:
-  - "https://cdnjs.cloudflare.com/ajax/libs/feather-icons/4.9.0/feather.min.js"
-  - "https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.7.3/Chart.min.js"
-  - "dashboard.js"
+  - src: "https://cdnjs.cloudflare.com/ajax/libs/feather-icons/4.22.1/feather.min.js"
+    integrity: "sha256-v7ozvh+7DfgbxrO6V1UgXsR+DDFHZr5ESbMWn6J5c8s="
+  - src: "https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.8.0/Chart.min.js"
+    integrity: "sha256-Uv9BNBucvCPipKQ2NS9wYpJmi8DTOEfTA/nH2aoJALw="
+  - src: "dashboard.js"
 ---
 
 <nav class="navbar navbar-dark fixed-top bg-dark flex-md-nowrap p-0 shadow">

site/content/docs/4.3/examples/offcanvas/index.html

@@ -4,7 +4,7 @@ title: Offcanvas template
 extra_css:
   - "offcanvas.css"
 extra_js:
-  - "offcanvas.js"
+  - src: "offcanvas.js"
 body_class: "bg-light"
 ---