Update minimum Node version to 8.

Author: iansu

packages/create-react-app/index.js

@@ -48,7 +48,7 @@ if (major < 4) {
       'You are running Node ' +
         currentNodeVersion +
         '.\n' +
-        'Create React App requires Node 4 or higher. \n' +
+        'Create React App requires Node 8 or higher. \n' +
         'Please update your version of Node.'
     )
   );

tasks/local-test.sh

@@ -8,7 +8,7 @@ function print_help {
   echo "Usage: ${0} [OPTIONS]"
   echo ""
   echo "OPTIONS:"
-  echo "  --node-version <version>  the node version to use while testing [6]"
+  echo "  --node-version <version>  the node version to use while testing [8]"
   echo "  --git-branch <branch>     the git branch to checkout for testing [the current one]"
   echo "  --test-suite <suite>      which test suite to use ('simple', installs', 'kitchensink', 'all') ['all']"
   echo "  --interactive             gain a bash shell after the test run"
@@ -18,7 +18,7 @@ function print_help {
 
 cd $(dirname $0)
 
-node_version=6
+node_version=8
 current_git_branch=`git rev-parse --abbrev-ref HEAD`
 git_branch=${current_git_branch}
 test_suite=all