Remove cafile hack used for npm6

updater/config/.npmrc

@@ -1,13 +1,6 @@
 # TODO: Remove these hacks once we've deprecated npm 6 support as it no longer
 # spwans a child process to npm install git dependencies.
 
-# Only set our custom CA cert for npm because the system ca's + our custom ca
-# causes npm to blow up when installing git dependencies (E2BIG exception). This
-# happens because the ca-file contents are passed as a cli argument to npm
-# install from npm/cli/lib/pack.js as --ca="contents of ca file" - "ca" is
-# populated automatically by npm when setting "--cafile" and passed through in
-# when spawning the cli to install git dependencies.
-cafile=/usr/local/share/ca-certificates/dbot-ca.crt
 # Because npm doesn't pass through all npm config when doing git installs in
 # npm/cli/lib/pack.js we also need to disable audit here to prevent npm from
 # auditing git dependencies, we do this to sped up installs