Pin to a specific clang version

We should investigate if it's possible to pin our build to a specific, well known version of clang, for a given release. For example, to guarantee that OSSM 2.2.z will always build with clang 13.0.1, regardless of the value of z.

If the clang version changes in the middle of a release, e.g., between OSSM 2.2.1 and 2.2.2, it might bring issues that didn't exist before, e.g, new errors that before were just warnings. This means we have to stop what we are doing in the middle of the sprint to fix such errors.

Ideally we should bump compiler versions between major and minor releases, not micro.

Here's a thread I started on google chat asking this question: https://chat.google.com/room/AAAATiT7PR8/DCsgK0lPMxM

We should look only at 2.2 and/or 2.3 builds, as previous versions use RPM builds and I think we are safe.