[bootlin/training-materials] bcf6d5: yocto: fix broken URL for the layer index

[Luca Ceresoli]

  Branch: refs/heads/master
  Home:   https://github.com/bootlin/training-materials
  Commit: bcf6d592bab2cbdfd63e32640d793ff3ffd72b4b
      https://github.com/bootlin/training-materials/commit/bcf6d592bab2cbdfd63e32640d793ff3ffd72b4b
  Author: Luca Ceresoli <luca.ceresoli at bootlin.com>
  Date:   2022-06-14 (Tue, 14 Jun 2022)

  Changed paths:
    M slides/yocto-layer/yocto-layer.tex

  Log Message:
  -----------
  yocto: fix broken URL for the layer index

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