Add comment to matlab.yml CI workflow explaining why it is useful to …

…explicitly pin the operating system version to `ubuntu-20.04

.github/workflows/matlab.yml

@@ -42,6 +42,22 @@ jobs:
 
   ubuntu:
     name: AMD64 Ubuntu 20.04 MATLAB
+    # Explicitly pin the Ubuntu version to 20.04 for the time being because:
+    #
+    #     1. The version of GLIBCXX shipped with Ubuntu 22.04 is not binary compatible
+    #        with the GLIBCXX bundled with MATLAB R2023a. This is a relatively common
+    #        issue.
+    #
+    #        For example, see:
+    #
+    #        https://www.mathworks.com/matlabcentral/answers/1907290-how-to-manually-select-the-libstdc-library-to-use-to-resolve-a-version-glibcxx_-not-found
+    #
+    #     2. The version of GLIBCXX shipped with Ubuntu 22.04 is not binary compatible with
+    #        the version of GLIBCXX shipped with Debian 11. Several of the Arrow community
+    #        members who work on the MATLAB bindings use Debian 11 locally for qualification.
+    #        Using Ubuntu 20.04 eases development workflows for these community members.
+    #
+    # In the future, we can investigate adding support for building against more Linux (e.g. `ubuntu-22.04`) and MATLAB versions (e.g. R2023b).
     runs-on: ubuntu-20.04
     if: ${{ !contains(github.event.pull_request.title, 'WIP') }}
     steps: