Update the cosign keyless documentation to point to the GA release. (#…

…1427)

Signed-off-by: Dan Lorenc <[email protected]>

KEYLESS.md

@@ -3,11 +3,12 @@
 The full design document for this can be found [here](https://docs.google.com/document/d/189w4Fp1GEA1b2P633HyqTwtcWFNTu_Af4meolMa_1_8/edit?resourcekey=0-QoqNqcHXvSuPnMUdn8RGOQ#heading=h.2mtrw7byet02)
 (join [email protected] for access).
 
-🚨 🚨 **ExPeRiMeNtAl** 🚨 🚨
-
-This document explains how the experimental `keyless` signatures work in `cosign`.
+This document explains how the `keyless` signatures work in `cosign`.
 Try it out!
 
+This signature mode relies on the Sigstore Public Good Instance, which is rapidly heading toward a GA release!
+We don't have a date yet, but follow along on the [GitHub project](https://github.com/orgs/sigstore/projects/5).
+
 ## Usage
 
 Keyless signing: