demo(dialog): add fields for minWidth, minHeight, maxWidth and maxHeight

Not adding `minWidth`, `minHeight`, `maxWidth` and `maxHeight` to `config` to avoid overriding the default value of `maxWidth` particularly—the type checker will require it to be a string. Instead, setting `config` to type `MatDialogConfig` is prefered to appease the type checker since those four properties are optional.

src/demo-app/dialog/dialog-demo.html

@@ -23,6 +23,24 @@ <h2>Dialog dimensions</h2>
       </mat-form-field>
     </p>
 
+    <p>
+      <mat-form-field>
+        <input matInput [(ngModel)]="config.minWidth" placeholder="Min Width">
+      </mat-form-field>
+      <mat-form-field>
+        <input matInput [(ngModel)]="config.minHeight" placeholder="Min Height">
+      </mat-form-field>
+    </p>
+
+    <p>
+      <mat-form-field>
+        <input matInput [(ngModel)]="config.maxWidth" placeholder="Max Width">
+      </mat-form-field>
+      <mat-form-field>
+        <input matInput [(ngModel)]="config.maxHeight" placeholder="Max Height">
+      </mat-form-field>
+    </p>
+
     <h2>Dialog position</h2>
 
     <p>

src/demo-app/dialog/dialog-demo.ts

@@ -1,6 +1,6 @@
 import {Component, Inject, ViewChild, TemplateRef} from '@angular/core';
 import {DOCUMENT} from '@angular/platform-browser';
-import {MatDialog, MatDialogRef, MAT_DIALOG_DATA} from '@angular/material';
+import {MatDialog, MatDialogConfig, MatDialogRef, MAT_DIALOG_DATA} from '@angular/material';
 
 
 @Component({
@@ -14,7 +14,7 @@ export class DialogDemo {
   lastAfterClosedResult: string;
   lastBeforeCloseResult: string;
   actionsAlignment: string;
-  config = {
+  config: Partial<MatDialogConfig> = {
     disableClose: false,
     panelClass: 'custom-overlay-pane-class',
     hasBackdrop: true,