Update html-webpack-plugin (#452)

* update html-webpack-plugin

* upgrade the manifest plugin

* try installing deps conditionally

* remove install

* not ubuntu latest

Author: agubler

.github/workflows/ci.yml

@@ -12,7 +12,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [ubuntu-latest, macos-latest, windows-latest]
+        os: [ubuntu-18.04, macos-latest, windows-latest]
         node-version: [12.x]
     timeout-minutes: 120
     runs-on: ${{ matrix.os }}