[bootlin/training-materials] 8afbcc: github action: install texlive-appendixnumberbeamer

[Luca Ceresoli]

  Branch: refs/heads/master
  Home:   https://github.com/bootlin/training-materials
  Commit: 8afbccf54980df2c817b46b8809847a448e4f578
      https://github.com/bootlin/training-materials/commit/8afbccf54980df2c817b46b8809847a448e4f578
  Author: Luca Ceresoli <luca.ceresoli at bootlin.com>
  Date:   2023-02-07 (Tue, 07 Feb 2023)

  Changed paths:
    M .github/actions/build-material-action/Dockerfile

  Log Message:
  -----------
  github action: install texlive-appendixnumberbeamer

Needed for Fedora after recent commit "slides: add provision for an "Extra section" in appendix".

Signed-off-by: Luca Ceresoli <luca.ceresoli at bootlin.com>