macos m1 nightly cron tests

.github/workflows/test_nightlies.yml

@@ -0,0 +1,29 @@
+on: [pull_request]
+#  schedule:
+#    - cron:  '0 15 * * *'
+
+name: Test latest nightly release for macOS Apple Silicon
+
+jobs:
+  test-and-build:
+    name: test nightly macos aarch64
+    runs-on: [self-hosted, macOS, ARM64]
+    timeout-minutes: 90
+    steps:
+      name: fetch releases data and save to file
+      run: curl https://api.github.com/repos/roc-lang/roc/releases > roc_releases.json
+
+      name: get the url of today's release for macos apple silicon
+      run: echo "RELEASE_URL=$(./ci/get_latest_release.sh)" >> $GITHUB_ENV
+
+      name: get the archive from the url
+      run: curl -OL ${{ env.RELEASE_URL }}
+
+      name: decompress the tar
+      run: ls | grep tar | xargs tar -xzvf
+
+      name: test roc hello world
+      run: ./roc examples/hello-world/main.roc
+
+
+        

ci/get_latest_release_url.sh

@@ -0,0 +1,13 @@
+#!/usr/bin/env bash
+
+# assumes roc_releases.json is present
+
+LATEST_RELEASE_URL=`cat roc_releases.json | jq --arg today $(date +'%Y-%m-%d') '.[0] | .assets | map(.browser_download_url) | map(select(. | contains("silicon-\($today)"))) | .[0]'`
+
+if [[ "$LATEST_RELEASE_URL" == "null" ]]
+then
+  echo "I expected to get a url but I got null instead. Today's release may not have been uploaded?"
+  exit 1
+else
+  echo $LATEST_RELEASE_URL | sed s/\"//g
+fi