doc: update minute-taking procedure for CTC

The doc says that the CTC moderator is responsible for taking minutes.

This change updates the doc to say that the moderator is responsible for
making sure that notes are taken, but not necessarily taking the notes
themselves.

PR-URL: https://github.com/nodejs/node/pull/9425
Reviewed-By: Josh Gavant <josh.gavant@outlook.com>
Reviewed-By: Evan Lucas <evanlucas@me.com>
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>

GOVERNANCE.md

@@ -143,8 +143,8 @@ items.
 The CTC may invite persons or representatives from certain projects to
 participate in a non-voting capacity.
 
-The meeting chair is responsible for summarizing the discussion of each agenda
-item and sending it as a pull request after the meeting.
+The meeting chair is responsible for ensuring that minutes are taken and that a
+pull request with the minutes is submitted after the meeting.
 
 Due to the challenges of scheduling a global meeting with participants in
 several timezones, the CTC will seek to resolve as many agenda items as possible