Add a compatibility table to the README

Specifies the versions of the action, CLI and GHES that are jointly compatible.

Author: aeisenberg

CHANGELOG.md

@@ -7,6 +7,7 @@ Note that the only difference between `v2` and `v3` of the CodeQL Action is the
 ## [UNRELEASED]
 
 - Update default CodeQL bundle version to 2.17.2. [#2270](https://github.com/github/codeql-action/pull/2270)
+- 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)
 
 ## 3.25.3 - 25 Apr 2024
 
@@ -30,7 +31,7 @@ No user facing changes.
 
   - The `setup-python-dependencies` input to the `init` Action
   - The `CODEQL_ACTION_DISABLE_PYTHON_DEPENDENCY_INSTALLATION` environment variable
-  
+
   We recommend removing any references to these from your workflows. For more information, see the release notes for CodeQL Action v3.23.0 and v2.23.0.
 - Automatically overwrite an existing database if found on the filesystem. [#2229](https://github.com/github/codeql-action/pull/2229)
 - Bump the minimum CodeQL bundle version to 2.12.6. [#2232](https://github.com/github/codeql-action/pull/2232)

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`    | `latest` | `github.com` |
+| `v3.25` | `v2.17`  | `v3.12`      |
+| `v3.24` | `v2.16`  | `v3.11`      |
+| `v3.22` | `v2.15`  | `v3.10`      |
+| `v3.21` | `v2.14`  | `v3.9`       |
+
+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).