Add a compatibility table to the README

CHANGELOG.md

@@ -6,12 +6,12 @@ Note that the only difference between `v2` and `v3` of the CodeQL Action is the
 
 ## [UNRELEASED]
 
-No user facing changes.
+- Add a compatibility matrix of supported CodeQL Action, CodeQL CLI, and GitHub Enterprise Server versions to the [README.md](README.md). [#2273](https://github.com/github/codeql-action/pull/2273)
+- Avoid printing out a warning for a missing `on.push` trigger when the CodeQL Action is triggered via a `workflow_call` event. [#2274](https://github.com/github/codeql-action/pull/2274)
 
 ## 3.25.4 - 08 May 2024
 
 - Update default CodeQL bundle version to 2.17.2. [#2270](https://github.com/github/codeql-action/pull/2270)
-- Avoid printing out a warning for a missing `on.push` trigger when the CodeQL Action is triggered via a `workflow_call` event. [#2274](https://github.com/github/codeql-action/pull/2274)
 
 ## 3.25.3 - 25 Apr 2024
 

CONTRIBUTING.md

@@ -3,6 +3,7 @@
 [fork]: https://github.com/github/codeql-action/fork
 [pr]: https://github.com/github/codeql-action/compare
 [code-of-conduct]: CODE_OF_CONDUCT.md
+[readme]: README.md#supported-versions-of-the-codeql-cli-and-github-enterprise-server
 
 Hi there! We're thrilled that you'd like to contribute to this project. Your help is essential for keeping it great.
 
@@ -84,6 +85,7 @@ We typically deprecate a version of CodeQL when the GitHub Enterprise Server (GH
 1. Notify users using the old version of CodeQL about the deprecation.
     - Update `CODEQL_NEXT_MINIMUM_VERSION`, `GHES_VERSION_MOST_RECENTLY_DEPRECATED`, and `GHES_MOST_RECENT_DEPRECATION_DATE` in `src/codeql.ts` to reflect the new minimum version of CodeQL and the GHES version that has just been deprecated.
     - Add a changelog note announcing the deprecation.
+    - Update the CLI version referenced in the [readme] by adding a new row to the compatibility table.
     - Example PR: https://github.com/github/codeql-action/pull/1884
 1. Release the Action, or wait for the next scheduled release of the Action, then wait at least a week so users have time to see and act on the deprecation warning.
 1. Remove support for the old version of CodeQL.

README.md

@@ -33,6 +33,22 @@ To provide the best experience to customers using older versions of GitHub Enter
 
 For more information, see "[Code scanning: deprecation of CodeQL Action v2](https://github.blog/changelog/2024-01-12-code-scanning-deprecation-of-codeql-action-v2/)."
 
+## Supported versions of the CodeQL CLI and GitHub Enterprise Server
+
+We typically release new minor versions of the CodeQL Action and CLI when a new minor version of GitHub Enterprise Server (GHES) is released. When a version of GHES is deprecated, the CodeQL Action and CLI releases that shipped with it are deprecated as well.
+
+| Recommended CodeQL Action | Recommended CodeQL CLI Version | GitHub Environment |
+|---------|----------|--------------|
+| `v3` | default (do not pass a `tools` input) | GitHub.com |
+| `3.22.12` | `2.15.5` | Enterprise Server 3.12 |
+| `2.22.1` | `2.14.6` | Enterprise Server 3.11 |
+| `2.20.3` | `2.13.5` | Enterprise Server 3.10 |
+| `2.2.9` | `2.12.5` | Enterprise Server 3.9 |
+
+CodeQL Action `v2` will stop receiving updates when GHES 3.11 is deprecated.
+
+See the full list of GHES release and deprecation dates at [GitHub Enterprise Server releases](https://docs.github.com/en/enterprise-server/admin/all-releases#releases-of-github-enterprise-server).
+
 ## Troubleshooting
 
 Read about [troubleshooting code scanning](https://docs.github.com/en/code-security/code-scanning/troubleshooting-code-scanning).