fix(ci/debianrepo): avoid running docker arm64 (#551)

The issue at https://github.com/ooni/probe/issues/1741 is that running `docker --platform linux/arm64` segfaults when running `sudo apt-get update -q` inside the `arm64` docker environment.

As far as the `debianrepo` rule is concerned, we can fix the issue by taking advantage of Debian multi-arch. We now configure Debian multi-arch and install the package inside a `debian:stable` environment.

We keep using docker. In principle we could not. But the Ubuntu environment provided by GitHub actions does not support multi-arch for arm. Also, I'd like testing this rule to be possible also locally (where I don't have Debian).

.github/workflows/debianrepo.yml

@@ -3,33 +3,36 @@ name: debianrepo
 on:
   push:
     branches:
+      - "stable"
       - "release/**"
+      - "master"
+      - "debianrepo"
 
 jobs:
   test_386:
     runs-on: "ubuntu-20.04"
     steps:
       - uses: actions/checkout@v2
-      - run: ./E2E/debian.sh docker i386
+      - run: sudo ./E2E/debian.sh docker i386
+      - run: sudo cat DEBIAN_INSTALLED_PACKAGE.txt
 
   test_amd64:
     runs-on: "ubuntu-20.04"
     steps:
       - uses: actions/checkout@v2
-      - run: ./E2E/debian.sh docker amd64
+      - run: sudo ./E2E/debian.sh docker amd64
+      - run: sudo cat DEBIAN_INSTALLED_PACKAGE.txt
 
   test_arm:
     runs-on: "ubuntu-20.04"
     steps:
       - uses: actions/checkout@v2
-      - run: sudo apt-get update -q
-      - run: sudo apt-get install -y qemu-user-static
-      - run: ./E2E/debian.sh docker armhf
+      - run: sudo ./E2E/debian.sh docker armhf
+      - run: sudo cat DEBIAN_INSTALLED_PACKAGE.txt
 
-  build_arm64:
+  test_arm64:
     runs-on: "ubuntu-20.04"
     steps:
       - uses: actions/checkout@v2
-      - run: sudo apt-get update -q
-      - run: sudo apt-get install -y qemu-user-static
-      - run: ./E2E/debian.sh docker arm64
+      - run: sudo ./E2E/debian.sh docker arm64
+      - run: sudo cat DEBIAN_INSTALLED_PACKAGE.txt