Update guidance of LibraryVersions.kt and LibraryGroups.kt

This is to match https://android-review.googlesource.com/c/platform/frameworks/support/+/1897444
where library groups and versions are stored in libraryversion.toml

PiperOrigin-RevId: 426503705
Change-Id: I7a8119773df93b964e5d3c0a5b2e270cd2a3ea6d
diff --git a/docs/versioning.md b/docs/versioning.md
index 88250d7..42bec31 100644
--- a/docs/versioning.md
+++ b/docs/versioning.md
@@ -339,8 +339,7 @@
 
 ### How to update your version
 
-1.  Update the version listed in
-    `frameworks/support/buildSrc/public/src/main/kotlin/androidx/build/LibraryVersions.kt`
+1.  Update the version listed in `frameworks/support/libraryversions.toml`
 1.  If your library is a `beta` or `rc01` version, run `./gradlew
     <your-lib>:updateApi`. This will create an API txt file for the new version
     of your library. For other versions, this step is not reqired