ci: add install-script

Author: anlyyao

.github/workflows/pr-compressed-size.yml

@@ -14,4 +14,5 @@ jobs:
       - uses: preactjs/compressed-size-action@v2
         with:
           repo-token: '${{ secrets.GITHUB_TOKEN }}'
+          install-script: 'npm install'
           pattern: './miniprogram_dist/**/*.{js,wxs,wxml,json}'