yarn was used everywhere else, and using `npm ci` required inclusion
of a package-lock.json which could have different dependencies than yarn.lock

this allows the use of one single yarn.lock, but the --frozen-lockfile argument
on yarn install in combination with purging node_modules emulates `npm ci`
behavior

this way we are in control of the version, npx may pull something in over
the network, which is unwanted in CI / release where we need total control

also improve caching of yarn items by adding a version key, in case
we need to forcibly remove caches in future

:-)

…h-example.sh

This includes all the current configuration items noted in app startup logs / native
integration guides

this improves the developer experience, all things noted or needed while
I was working with the example to update the android SDK

BREAKING CHANGE: upstream SDKs removed updateUserProperties, there is no replacement

…K 31

this proves Android targetSdk 31 works, when combined with facebook-android-sdk v12

note that we are not compatible with the new flow types, they get stricter
every time. maintenance effort will be spent on typescript, with apologies

feel free to post a PR that brings flow types up to v158 and re-enables
the check in the CI test workflow

Fixes thebergamo#102

this will fix the build in CI for iOS at the same time it ensures
we run CI against the actual development code (vs github master, which
is what yarn installs by default)

pod install will fail on ubuntu (when building android) so allow it to fail
with the `|| true` bit, but we still install the dev code dependencies so
android tests actual dev code