chore: drop Node.js v8 support (#5365)

* chore: update relevant Node.js versions from 8 to 10

* chore: remove node6 and node8 folders from puppeteer-firefox ci

* fix: loosen definition for proc.stdio

* fix: update typescript version used in npm run test-types

experimental/puppeteer-firefox/.ci/node10/Dockerfile.linux

@@ -1,4 +1,4 @@
-FROM node:6.12.3
+FROM node:10.18.1-stretch
 
 RUN apt-get update && \
     apt-get -y install xvfb gconf-service libasound2 libatk1.0-0 libc6 libcairo2 libcups2 \

experimental/puppeteer-firefox/.ci/node10/Dockerfile.windows

@@ -1,6 +1,6 @@
 FROM microsoft/windowsservercore:latest
 
-ENV NODE_VERSION 8.11.3
+ENV NODE_VERSION 10.18.1
 
 RUN setx /m PATH "%PATH%;C:\nodejs"
 

experimental/puppeteer-firefox/.ci/node8/Dockerfile.linux

@@ -1,17 +0,0 @@
-FROM node:8.11.3-stretch
-
-RUN apt-get update && \
-    apt-get -y install xvfb gconf-service libasound2 libatk1.0-0 libc6 libcairo2 libcups2 \
-      libdbus-1-3 libexpat1 libfontconfig1 libgcc1 libgconf-2-4 libgdk-pixbuf2.0-0 libglib2.0-0 \
-      libgtk-3-0 libnspr4 libpango-1.0-0 libpangocairo-1.0-0 libstdc++6 libx11-6 libx11-xcb1 libxcb1 \
-      libxcomposite1 libxcursor1 libxdamage1 libxext6 libxfixes3 libxi6 libxrandr2 libxrender1 libxss1 \
-      libxtst6 ca-certificates fonts-liberation libappindicator1 libnss3 lsb-release xdg-utils wget && \
-    rm -rf /var/lib/apt/lists/*
-
-# Add user so we don't need --no-sandbox.
-RUN groupadd -r pptruser && useradd -r -g pptruser -G audio,video pptruser \
-    && mkdir -p /home/pptruser/Downloads \
-    && chown -R pptruser:pptruser /home/pptruser
-
-# Run everything after as non-privileged user.
-USER pptruser

experimental/puppeteer-firefox/.cirrus.yml

@@ -2,30 +2,30 @@ env:
   DISPLAY: :99.0
 
 task:
-  name: node8 (linux)
+  name: node10 (linux)
   container:
-    dockerfile: .ci/node8/Dockerfile.linux
+    dockerfile: .ci/node10/Dockerfile.linux
   xvfb_start_background_script: Xvfb :99 -ac -screen 0 1024x768x24
   install_script: npm install
   test_script: npm run fjunit
 
 task:
-  name: node8 (macOS)
+  name: node10 (macOS)
   osx_instance:
     image: high-sierra-base
   env:
     HOMEBREW_NO_AUTO_UPDATE: 1
   node_install_script:
-    - brew install node@8
-    - brew link --force node@8
+    - brew install node@10
+    - brew link --force node@10
   install_script: npm install
   test_script: npm run fjunit
 
 # task:
 #   allow_failures: true
 #  windows_container:
-#    dockerfile: .ci/node8/Dockerfile.windows
+#    dockerfile: .ci/node10/Dockerfile.windows
 #    os_version: 2016
-#  name: node8 (windows)
+#  name: node10 (windows)
 #  install_script: npm install --unsafe-perm
 #  test_script: npm run fjunit

experimental/puppeteer-firefox/package.json

@@ -6,7 +6,7 @@
   "repository": "github:puppeteer/puppeteer",
   "homepage": "https://github.com/puppeteer/puppeteer/tree/master/experimental/puppeteer-firefox",
   "engines": {
-    "node": ">=8.9.4"
+    "node": ">=10.18.1"
   },
   "puppeteer": {
     "firefox_revision": "v0.0.1"