meta: update GOVERNANCE.md to reflect TSC charter changes

Refer to TSC voting members where necessary.

Ref: nodejs/TSC#1350

GOVERNANCE.md

@@ -74,7 +74,7 @@ has authored or approved a commit that has landed.
 ## Technical Steering Committee
 
 A subset of the collaborators forms the Technical Steering Committee (TSC).
-The TSC has final authority over this project, including:
+The TSC voting members have final authority over this project, including:
 
 * Technical direction
 * Project governance and process (including this policy)
@@ -103,8 +103,8 @@ something. If consensus-seeking fails for an issue, a collaborator may apply the
 `tsc-agenda` label. That will add it to the TSC meeting agenda.
 
 Before each TSC meeting, the meeting chair will share the agenda with members of
-the TSC. TSC members can also add items to the agenda at the beginning of each
-meeting. The meeting chair and the TSC cannot veto or remove items.
+the TSC. TSC voting members can also add items to the agenda at the beginning of
+each meeting. The meeting chair and the TSC cannot veto or remove items.
 
 The TSC may invite people to take part in a non-voting capacity.
 
@@ -118,8 +118,8 @@ the issue tracker is:
 
 * A TSC member opens an issue explaining the proposal/issue and @-mentions
   @nodejs/tsc.
-* The proposal passes if, after 72 hours, there are two or more TSC approvals
-  and no TSC opposition.
+* The proposal passes if, after 72 hours, there are two or more TSC voting
+  member approvals and no TSC voting member opposition.
 * If there is an extended impasse, a TSC member may make a motion for a vote.
 
 ## Collaborator nominations