doc: update Mac OS X references in releases.md

This commit updates 3 additional references to Mac OS X in
releases.md to macOS.

Fixes: nodejs/node#12086
PR-URL: nodejs/node#12106
Backport-PR-URL: nodejs/node#12650
Reviewed-By: Vse Mozhet Byt <vsemozhetbyt@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Gibson Fahnestock <gibfahn@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

doc/releases.md

@@ -188,13 +188,13 @@ Perform some smoke-testing. We have [citgm](https://github.com/nodejs/citgm) for
 
 If there is a reason to produce a test release for the purpose of having others try out installers or specifics of builds, produce a nightly build using **[iojs+release](https://ci-release.nodejs.org/job/iojs+release/)** and wait for it to drop in <https://nodejs.org/download/nightly/>. Follow the directions and enter a proper length commit SHA, enter a date string, and select "nightly" for "disttype".
 
-This is particularly recommended if there has been recent work relating to the OS X or Windows installers as they are not tested in any way by CI.
+This is particularly recommended if there has been recent work relating to the macOS or Windows installers as they are not tested in any way by CI.
 
 ### 8. Produce Release Builds
 
 Use **[iojs+release](https://ci-release.nodejs.org/job/iojs+release/)** to produce release artifacts. Enter the commit that you want to build from and select "release" for "disttype".
 
-Artifacts from each slave are uploaded to Jenkins and are available if further testing is required. Use this opportunity particularly to test OS X and Windows installers if there are any concerns. Click through to the individual slaves for a run to find the artifacts.
+Artifacts from each slave are uploaded to Jenkins and are available if further testing is required. Use this opportunity particularly to test macOS and Windows installers if there are any concerns. Click through to the individual slaves for a run to find the artifacts.
 
 All release slaves should achieve "SUCCESS" (and be green, not red). A release with failures should not be promoted as there are likely problems to be investigated.
 
@@ -204,7 +204,7 @@ If you have an error on Windows and need to start again, be aware that you'll ge
 
 ARMv7 takes the longest to compile. Unfortunately ccache isn't as effective on release builds, I think it's because of the additional macro settings that go in to a release build that nullify previous builds. Also most of the release build machines are separate to the test build machines so they don't get any benefit from ongoing compiles between releases. You can expect 1.5 hours for the ARMv7 builder to complete and you should normally wait for this to finish. It is possible to rush a release out if you want and add additional builds later but we normally provide ARMv7 from initial promotion.
 
-You do not have to wait for the ARMv6 / Raspberry PI builds if they take longer than the others. It is only necessary to have the main Linux (x64 and x86), OS X .pkg and .tar.gz, Windows (x64 and x86) .msi and .exe, source, headers and docs (both produced currently by an OS X slave). **If you promote builds _before_ ARM builds have finished, you must repeat the promotion step for the ARM builds when they are ready**.
+You do not have to wait for the ARMv6 / Raspberry PI builds if they take longer than the others. It is only necessary to have the main Linux (x64 and x86), macOS .pkg and .tar.gz, Windows (x64 and x86) .msi and .exe, source, headers and docs (both produced currently by an macOS slave). **If you promote builds _before_ ARM builds have finished, you must repeat the promotion step for the ARM builds when they are ready**.
 
 ### 9. Test the Build