feat(make): build miniooni (#322)

This change is useful to move forward with blessing a new
release (https://github.com/ooni/probe/issues/1439).

.github/workflows/ios.yml

@@ -1,8 +1,10 @@
+# ios verifies we can still build for iOS
 name: ios
 on:
   push:
     branches:
       - 'release/**'
+      - 'master'
 jobs:
   test:
     runs-on: macos-10.15