CI: add requirements-tox-py3x-check-uc job on AArch64

There are moments when bumping versions breaks all non-x86 builds
because upstream forgets to upload source tarball to Pypi.

As we need librdkafka 1.4.0+ we build version from Debian 'testing'.

Change-Id: Ib4a4eac5e5f14eab8104fb8fe4f49c90e333dab0

.zuul.d/jobs.yaml

@@ -55,3 +55,11 @@
     vars:
       tox_envlist: bindep
 
+- job:
+    name: requirements-tox-py38-check-uc-aarch64
+    parent: requirements-tox-py38-check-uc
+    nodeset: ubuntu-focal-arm64
+    timeout: 7200
+    pre-run: playbooks/build-kafka.yaml
+    vars:
+      ansible_python_interpreter: python3

.zuul.d/project.yaml

@@ -53,6 +53,10 @@
               - ^setup.cfg$
     check-arm64:
       jobs:
+        - requirements-tox-py38-check-uc-aarch64:
+            files:
+              - bindep.txt
+              - upper-constraints.txt
         - build-wheel-cache-centos-8-arm64:
             files:
               - bindep.txt

playbooks/build-kafka.yaml

@@ -0,0 +1,43 @@
+- hosts: all
+  tasks:
+    - name: Build and install librdkafka 1.4.0+
+      block:
+        - name: Install librdkafka build dependencies
+          apt:
+            name:
+              - liblz4-dev
+              - libsasl2-dev
+              - libssl-dev
+              - libzstd-dev
+              - python3
+              - zlib1g-dev
+              - debhelper
+              - devscripts
+              - wget
+              - build-essential
+            state: present
+            install_recommends: no
+          become: true
+
+        - name: Create build directory
+          tempfile:
+            state: directory
+          register: build_dir
+
+        - name: Fetch librdkafka from Debian 'testing'
+          command: "dget -u https://snapshot.debian.org/archive/debian/20200513T084344Z/pool/main/libr/librdkafka/librdkafka_1.4.2-1.dsc"
+          args:
+            chdir: "{{ build_dir.path }}"
+
+          # NOTE(hrw): use '-d' to skip 'error: Unmet build dependencies: debhelper-compat (= 13)'
+        - name: Build librdkafka package
+          shell:
+            cmd: |
+              set +o errexit
+              set -o xtrace
+
+              debuild -b -d
+              ls -l ../*
+              sudo debi
+            executable: /bin/bash
+            chdir: "{{ build_dir.path }}/librdkafka-1.4.2/"