feat: Extend Extensions Support for Mipmap Plugin (pixijs#166)

* feat: add support to '.webp' and '.avif' in mipmap

* chore: fix lint warnings

---------

Co-authored-by: Zyie <[email protected]>

Author: Andrek25

packages/assetpack/src/image/mipmap.ts

@@ -41,7 +41,9 @@ export function mipmap(defaultOptions: MipmapOptions = {}): AssetPipe<MipmapOpti
             nomip: 'nomip',
         },
         test(asset: Asset, options) {
-            return options && checkExt(asset.path, '.png', '.jpg', '.jpeg') && !asset.allMetaData[this.tags!.nomip];
+            const extensions = ['.png', '.jpg', '.jpeg', '.webp', '.avif'];
+
+            return options && checkExt(asset.path, ...extensions) && !asset.allMetaData[this.tags!.nomip];
         },
         async transform(asset: Asset, options) {
             const shouldMipmap = mipmap && !asset.allMetaData[this.tags!.fix];