Updated next/experimental release version docs (#3748)

To account for changes made in PR facebook/react/pull/21700

Author: Brian Vaughn

content/docs/release-channels.md

@@ -18,7 +18,7 @@ Each of React's release channels is designed for a distinct use case:
 - [**Next**](#next-channel) tracks the master branch of the React source code repository. Think of these as release candidates for the next minor semver release. Use this for integration testing between React and third party projects.
 - [**Experimental**](#experimental-channel) includes experimental APIs and features that aren't available in the stable releases. These also track the master branch, but with additional feature flags turned on. Use this to try out upcoming features before they are released.
 
-All releases are published to npm, but only Latest uses [semantic versioning](/docs/faq-versioning.html). Prereleases (those in the Next and Experimental channels) have versions generated from a hash of their contents, e.g. `0.0.0-1022ee0ec` for Next and `0.0.0-experimental-1022ee0ec` for Experimental.
+All releases are published to npm, but only Latest uses [semantic versioning](/docs/faq-versioning.html). Prereleases (those in the Next and Experimental channels) have versions generated from a hash of their contents and the commit date, e.g. `0.0.0-68053d940-20210623` for Next and `0.0.0-experimental-68053d940-20210623` for Experimental.
 
 **The only officially supported release channel for user-facing applications is Latest**. Next and Experimental releases are provided for testing purposes only, and we provide no guarantees that behavior won't change between releases. They do not follow the semver protocol that we use for releases from Latest.
 
@@ -40,7 +40,7 @@ The degree of change between the most recent Next release and the most recent La
 
 **Do not use prereleases in user-facing applications.**
 
-Releases in Next are published with the `next` tag on npm. Versions are generated from a hash of the build's contents, e.g. `0.0.0-1022ee0ec`.
+Releases in Next are published with the `next` tag on npm. Versions are generated from a hash of the build's contents and the commit date, e.g. `0.0.0-68053d940-20210623`.
 
 #### Using the Next Channel for Integration Testing {#using-the-next-channel-for-integration-testing}
 
@@ -76,7 +76,7 @@ Usually, an update to Next is accompanied by a corresponding update to Experimen
 
 Experimental releases may be significantly different than releases to Next and Latest. **Do not use Experimental releases in user-facing applications.** You should expect frequent breaking changes between releases in the Experimental channel.
 
-Releases in Experimental are published with the `experimental` tag on npm. Versions are generated from a hash of the build's contents, e.g. `0.0.0-experimental-1022ee0ec`.
+Releases in Experimental are published with the `experimental` tag on npm. Versions are generated from a hash of the build's contents and the commit date, e.g. `0.0.0-experimental-68053d940-20210623`.
 
 #### What Goes Into an Experimental Release? {#what-goes-into-an-experimental-release}