v1.2.0

This is the first version of splunk-otel-android that is based on the upstream version of
opentelemetry-android. Please note that this requires an additional project dependency,
as documented here.

• Depend on upstream opentelemetry-android (#640)
• Depend on updated java semantic conventions (#658)
• Feature enhancement: The instrumentation can now be configured to buffer telemetry created when
  your application is launched in the background. This buffered telemetry is sent when the
  app is foregrounded, or dropped when a new app session is started. Thanks to @rezastallone
  for this contribution. (#648)
• Update to opentelemetry-java sdk 1.31.0
• Update to opentelemetry-java-instrumentation 1.31.0