In an open source project, such as one typically found on GitHub, there are users who can submit pull requests and users who can merge them. It is my understanding that "contributor" is the term for the former group. What is the term for the latter group?
"Committers" is a common (and unsurprising) name.
Some projects make the distinction between "Maintainers" (who are responsible for participating in decisions about the project's direction and ultimately reaching consensus about them) and "Committers" (who actually merge, or commit patches), while some projects use them interchangeably.