build on Ubuntu 22.04 for x64 Linux

Author: d-sonuga

.github/workflows/dusk.yml

@@ -22,7 +22,16 @@ jobs:
           aarch64-unknown-linux-gnu,
         ]
         include:
-          - os: linux-gh-4-16-150
+          # Using Ubuntu 22.04 to keep min. glibc version as 2.35.
+          #
+          # The reason for doing this is so that the CI can pass for the
+          # toolchain upgrade.
+          # The min. glibc version required for a rust toolchain is the version present in the environment 
+          # that the toolchain is built in.
+          # At this time, core uses Ubuntu 22.04 (glibc 2.35). Since most tests in the rusk CI run on core, 
+          # then building on the `linux-gh-4-16-150` runner which uses Ubuntu 24.04 (glibc 2.39) will lead 
+          # to incompatibilities.
+          - os: core
             target: x86_64-unknown-linux-gnu
           - os: macos-latest-large
             target: x86_64-apple-darwin
@@ -38,8 +47,8 @@ jobs:
           fetch-depth: 0
 
       - name: Setup dependencies
-        if: matrix.os == 'ubuntu-latest'
-        run: sudo apt update && sudo apt install -y ninja-build
+        if: matrix.os == 'core'
+        run: apt update && apt install -y ninja-build
 
       - name: Setup dependencies
         if: startsWith(matrix.os, 'macos')