PostgreSQL is now in beta mode (#3772)

* PostgreSQL is now in beta mode

* Update CHANGELOG.md

* two -> three

Co-authored-by: Roger Ng <roger2hk@gmail.com>

---------

Co-authored-by: Roger Ng <roger2hk@gmail.com>

Author: robstradling

CHANGELOG.md

@@ -14,6 +14,7 @@
 * Fix error checking for QueueLeaves and AddSequencedLeaves in the PostgreSQL storage backend by @robstradling in https://github.com/google/trillian/pull/3752
 * Add an optimized QueueLeaves implementation for single-leaf batches in the PostgreSQL storage backend by @robstradling in https://github.com/google/trillian/pull/3769
 * Improve PostgreSQL functions by @robstradling in https://github.com/google/trillian/pull/3770
+* PostgreSQL is now in beta mode by @robstradling in https://github.com/google/trillian/pull/3772
 
 ### Misc
 

docs/Feature_Implementation_Matrix.md

@@ -64,7 +64,7 @@ The Log storage implementations supporting the original Trillian log.
 | CloudSpanner    | Beta     |                     | Google maintains continuous-integration environment based on CloudSpanner.  |
 | MySQL            | GA      | ✓                   |                                                                             |
 | CockroachDB      | Alpha   |                     | Supported by [Equinix Metal](https://deploy.equinix.com/).                  |
-| PostgreSQL       | Alpha   |                     | Supported by [Rob Stradling](https://github.com/robstradling) at [Sectigo](https://github.com/sectigo). |
+| PostgreSQL       | Beta    |                     | Supported by [Rob Stradling](https://github.com/robstradling) at [Sectigo](https://github.com/sectigo). |
 
 ##### Spanner
 This is a Google-internal implementation, and is used by all of Google's current Trillian deployments.
@@ -92,9 +92,9 @@ It's currently in alpha mode and is not yet in production use.
 
 ##### PostgreSQL
 
-This implementation has been tested with PostgreSQL 17.0.
+This implementation has been tested with PostgreSQL 17.0 and 13.20.
 
-It's currently in alpha mode and is not yet in production use.
+It's currently in beta mode, and is used by some of Sectigo's current Trillian deployments.
 
 ### Monitoring
 
@@ -126,7 +126,7 @@ Supported frameworks for quota management.
 | MySQL           | Beta    | ?                   |                                                                             |
 | Redis           | Alpha   | ✓                   |                                                                             |
 | CockroachDB     | Alpha   |                     | Supported by [Equinix Metal](https://deploy.equinix.com/).                  |
-| PostgreSQL      | Alpha   |                     | Supported by [Rob Stradling](https://github.com/robstradling) at [Sectigo](https://github.com/sectigo). |
+| PostgreSQL      | Beta    |                     | Supported by [Rob Stradling](https://github.com/robstradling) at [Sectigo](https://github.com/sectigo). |
 
 ### Key management
 

storage/README.md

@@ -5,17 +5,17 @@
 The interface, various concrete implementations, and any associated components
 live here. Interfaces and types are defined at the top level package.
 
-Currently, there are two usable storage implementation for logs:
+Currently, there are three usable storage implementation for logs:
    * MySQL/MariaDB in the [mysql/](mysql) package.
    * Cloud Spanner in the [cloudspanner](cloudspanner) package.
+   * PostgreSQL in the [postgresql/](postgresql) package (in beta mode).
 
 The MySQL / MariaDB implementation includes support for Maps. This has not yet
 been implemented by Cloud Spanner. There may be other storage implementations
 available from third parties.
 
 These implementations are in alpha mode and are not yet ready to be used by
 real applications:
-   * PostgreSQL in the [postgresql/](postgresql) package.
    * CockroachDB in the [crdb/](crdb) package.
 
 These implementations are for test purposes only and should not be used by real