ci: the VM tests only run on release branches (main only gets tested release branches)

.github/workflows/vmtest.yml

@@ -8,10 +8,11 @@
 # Needs the secret GIT_UPRISER_URL (the mirror's address, for the ISO). Every job has its own runner, so everything runs in parallel: one job per boot loader and per suite, each with its own VMs (2 vCPUs, 4-6 GB).
 name: Steamify VM tests
 
-# Only on main and the release branches (and by hand): the runners' time is limited, so not on every pull request.
+# Only on the release branches (and by hand): the runners' time is limited, so not on every pull request, and not on
+# main either, which only ever gets a release branch that was tested here.
 on:
   push:
-    branches: [main, 'release/**']
+    branches: ['release/**']
   workflow_dispatch:
 
 # A new run on the same branch stops the old one.
@@ -53,7 +54,10 @@ jobs:
         if: steps.cache.outputs.cache-hit != 'true'
         run: |
           sudo mkdir -p /mnt/work/iso && sudo chown -R "$USER" /mnt/work
-          curl -fL --retry 5 --retry-all-errors -o /mnt/work/iso/steamify.iso "${{ steps.find.outputs.url }}"
+          # 16 connections: one TCP stream from the mirror to the US stays at a few MB/s whatever the uplink is.
+          sudo apt-get install -y -qq aria2
+          aria2c -x16 -s16 -k8M --file-allocation=none --summary-interval=30 --console-log-level=warn --max-tries=5 --retry-wait=5 \
+              -d /mnt/work/iso -o steamify.iso "${{ steps.find.outputs.url }}"
           ls -la /mnt/work/iso
 
   boot: