fix(card): change image path to https in example (#7800)

Author: donroyco

src/material-examples/card-fancy/card-fancy-example.css

@@ -3,6 +3,6 @@
 }
 
 .example-header-image {
-  background-image: url('http://material.angular.io/assets/img/examples/shiba1.jpg');
+  background-image: url('https://material.angular.io/assets/img/examples/shiba1.jpg');
   background-size: cover;
 }

src/material-examples/card-fancy/card-fancy-example.html

@@ -4,7 +4,7 @@
     <mat-card-title>Shiba Inu</mat-card-title>
     <mat-card-subtitle>Dog Breed</mat-card-subtitle>
   </mat-card-header>
-  <img mat-card-image src="http://material.angular.io/assets/img/examples/shiba2.jpg" alt="Photo of a Shiba Inu">
+  <img mat-card-image src="https://material.angular.io/assets/img/examples/shiba2.jpg" alt="Photo of a Shiba Inu">
   <mat-card-content>
     <p>
       The Shiba Inu is the smallest of the six original and distinct spitz breeds of dog from Japan.