github: actions: update Ubuntu version

> Deprecation will begin on 2025-02-01 and the image will be fully
> unsupported by 2025-04-01.
>
> To raise awareness of the upcoming removal, we will temporarily fail
> jobs using Ubuntu 20.04. Builds that are scheduled to run during the
> brownout periods will fail.

Source: actions/runner-images#11101

Signed-off-by: Théo Lebrun <theo.lebrun@bootlin.com>

Author: tleb

.github/workflows/training-materials.yml

@@ -1,7 +1,7 @@
 on: [push, pull_request]
 jobs:
   embedded-linux:
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v3
       - uses: ./.github/actions/build-material-action
@@ -18,7 +18,7 @@ jobs:
             embedded-linux-labs.tar.xz
             embedded-linux-qemu-labs.tar.xz
   linux-kernel:
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v3
       - uses: ./.github/actions/build-material-action
@@ -35,7 +35,7 @@ jobs:
             linux-kernel-labs.tar.xz
             linux-kernel-beagleplay-labs.tar.xz
   buildroot:
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v3
       - uses: ./.github/actions/build-material-action
@@ -52,7 +52,7 @@ jobs:
             buildroot-labs.tar.xz
             buildroot-stm32-labs.tar.xz
   yocto:
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v3
       - uses: ./.github/actions/build-material-action
@@ -72,7 +72,7 @@ jobs:
             yocto-stm32-labs.tar.xz
             yocto-beagleplay-labs.tar.xz
   boot-time:
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v3
       - uses: ./.github/actions/build-material-action
@@ -86,7 +86,7 @@ jobs:
             boot-time-online-fr-agenda.pdf
             boot-time-labs.tar.xz
   graphics:
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v3
       - uses: ./.github/actions/build-material-action
@@ -98,7 +98,7 @@ jobs:
             graphics-online-agenda.pdf
             graphics-online-fr-agenda.pdf
   autotools:
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v3
       - uses: ./.github/actions/build-material-action
@@ -109,7 +109,7 @@ jobs:
             autotools-agenda.pdf
             autotools-labs.tar.xz
   preempt-rt:
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v3
       - uses: ./.github/actions/build-material-action
@@ -121,7 +121,7 @@ jobs:
             preempt-rt-online-fr-agenda.pdf
             preempt-rt-labs.tar.xz
   debugging:
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v3
       - uses: ./.github/actions/build-material-action
@@ -135,7 +135,7 @@ jobs:
             full-debugging-labs.pdf
             debugging-labs.tar.xz
   audio:
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v3
       - uses: ./.github/actions/build-material-action