ci: avoid the slow Azure Ubuntu package mirror

.github/actions/ubuntu-mirrors/action.yml

@@ -0,0 +1,15 @@
+name: Ubuntu archive mirrors
+description: Use Ubuntu's archives without the slow Azure mirror
+runs:
+  using: composite
+  steps:
+    - shell: bash
+      run: |
+        # Hosted Ubuntu images use this mirror list for all Ubuntu suites.
+        # Azure transfers can stay slow enough to exhaust the job without
+        # triggering apt's connection timeout. Keep the other image mirrors.
+        # https://github.com/actions/runner-images/issues/12949
+        grep -qF 'mirror+file:/etc/apt/apt-mirrors.txt' /etc/apt/sources.list.d/ubuntu.sources
+        sudo sed -i '\|^http://azure\.archive\.ubuntu\.com/|d' /etc/apt/apt-mirrors.txt
+        test -s /etc/apt/apt-mirrors.txt
+        cat /etc/apt/apt-mirrors.txt

.github/workflows/smoke.yml

@@ -96,6 +96,10 @@ jobs:
         with:
           gradle-version: "8.14.4"
 
+      - name: Ubuntu archive mirrors
+        if: runner.os == 'Linux'
+        uses: ./.github/actions/ubuntu-mirrors
+
       - name: System deps (Linux)
         if: runner.os == 'Linux'
         run: |
@@ -321,6 +325,9 @@ jobs:
 
       - uses: oven-sh/setup-bun@0c5077e51419868618aeaa5fe8019c62421857d6 # v2.2.0
 
+      - name: Ubuntu archive mirrors
+        uses: ./.github/actions/ubuntu-mirrors
+
       - name: System deps
         run: |
           sudo apt-get update