Install any missing deps after merging in updates from remote.

post_merge_deps_update.sh

# capture info messages and any errors in a log file
exec >> log/hooks-out.log 2>&1

if git diff-tree --name-only --no-commit-id ORIG_HEAD HEAD | grep -q 'package.json'; then
  echo "$(date): reinstalling deps since package.json changed"
  yarn > /dev/null
else
  echo "$(date): no changes detected in package.json"
fi

# link is needed: ln -fv [script location] .git/hooks/