Use Cirrus also for Aarch64 CI (#47)

.cirrus.yml

@@ -1,7 +1,11 @@
-freebsd_instance:
-  image: freebsd-13-0-release-amd64
 task:
-  name: FreeBSD
+  matrix:
+    - name: FreeBSD
+      freebsd_instance:
+        image_family: freebsd-13-1
+    - name: Linux ARMv8
+      arm_container:
+        image: ubuntu:latest
   env:
     matrix:
       - JULIA_VERSION: 1.3
@@ -12,11 +16,25 @@ task:
       - JULIA_VERSION: 1
       - JULIA_VERSION: nightly
   allow_failures: $JULIA_VERSION == 'nightly'
-  install_script:
-    - sh -c "$(fetch https://raw.githubusercontent.com/ararslan/CirrusCI.jl/master/bin/install.sh -o -)"
+  install_script: |
+    URL="https://raw.githubusercontent.com/ararslan/CirrusCI.jl/master/bin/install.sh"
+    set -x
+    if command -v apt; then
+        apt update
+        apt install -y curl
+    fi
+    if [ ! -z "$(which curl)" ]; then
+        sh -c "$(curl ${URL})"
+    elif [ ! -z "$(which wget)" ]; then
+        sh -c "$(wget ${URL} -O-)"
+    elif command -v fetch; then
+        sh -c "$(fetch ${URL} -o -)"
+    else
+        echo "No downloader installed! :( Install one! :)"
+    fi
   build_script:
     - cirrusjl build
   test_script:
     - cirrusjl test
   coverage_script:
-    - cirrusjl coverage codecov coveralls
+    - cirrusjl coverage codecov