Create a process for updating proguard rules

[ptornhult]

There seems to be quite a few open R8/Proguard issues, so more people than we are running into repeated issues with your library and obfuscation issues.

I'm not sure this is exactly how/if it works, but maybe you could add:
isMinifyEnabled = true
to the release target of the testapps project to test obfuscation works with the latest library dependency.

If your assembleRelease task fail, you should see the missing rules in: testapps/build/outputs/mapping/release/missing_rules.txt

And those new rules should be added to msal/consumer-rules.pro

Note! Currently the msal version of the testapp is set to "5.10.0", but it should be set to the same/latest version which is now 7.0.3