travis: Add test for arm64 (#399)

Signed-off-by: ossdev07 <ossdev@puresoftware.com>

.travis.yml

@@ -2,7 +2,9 @@ version: ~> 1.0
 dist: xenial
 language: python
 cache: pip
-
+arch:
+   - amd64
+   - arm64
 python:
   # Available Python (PyPy) can be listed by:
   #
@@ -38,6 +40,21 @@ matrix:
       script:
         - docker run --rm -v `pwd`:/io -w /io $DOCKER_IMAGE /io/docker/runtests.sh
 
+    - arch: arm64
+      name: arm64 32bit build
+      language: python
+      services:
+        - docker
+      env:
+        - DOCKER_IMAGE=quay.io/pypa/manylinux2014_aarch64
+      install:
+        - pip install -U pip
+        - pip install -r requirements.txt
+        - make cython
+        - docker pull $DOCKER_IMAGE
+      script:
+        - docker run --rm -v `pwd`:/io -w /io $DOCKER_IMAGE /io/docker/runtests.sh
+
     - name: "Python 2 (fallback)"
       python: "2.7"
       <<: *pure