Bump @pika/plugin-copy-assets from 0.6.1 to 0.8.1

Bumps [@pika/plugin-copy-assets](https://github.com/pikapkg/builders) from 0.6.1 to 0.8.1.
- [Release notes](https://github.com/pikapkg/builders/releases)
- [Commits](FredKSchott/pika-pack-builders@v0.6.1...v0.8.1)

Signed-off-by: dependabot-preview[bot] <[email protected]>

Author: dependabot-preview[bot]

package-lock.json

@@ -65,7 +65,7 @@
   "devDependencies": {
     "@pika/pack": "^0.5.0",
     "@pika/plugin-build-node": "^0.8.1",
-    "@pika/plugin-copy-assets": "^0.6.0",
+    "@pika/plugin-copy-assets": "^0.8.1",
     "@pika/plugin-ts-standard-pkg": "^0.8.1",
     "@types/jest": "^24.0.13",
     "@types/js-yaml": "^3.12.1",