title: firebase_core trying to use bintray
body: <p>I'm getting an error with firebase packages, in particular I think firebase_core,</p>
  <p>From what I can tell it's trying to get something from bintray, which is now shut down so it makes sense that it doesn't work. I'm using the latest version of <code>firebase_core: ^1.10.5</code> and <code>flutter 2.8.0</code> and dart <code>2.15.0</code></p>
  <p>Error:</p>
  <pre><code>FAILURE: Build failed with an exception.
  
  * What went wrong:
  Could not determine the dependencies of task ':app:processDebugResources'.
  &gt; Could not resolve all task dependencies for configuration ':app:debugRuntimeClasspath'.
     &gt; Could not resolve io.grpc:grpc-core:[1.41.0].
       Required by:
           project :app &gt; project :cloud_firestore &gt; com.google.firebase:firebase-firestore:24.0.0 &gt; io.grpc:grpc-android:1.41.0
           project :app &gt; project :cloud_firestore &gt; com.google.firebase:firebase-firestore:24.0.0 &gt; io.grpc:grpc-okhttp:1.41.0
        &gt; Failed to list versions for io.grpc:grpc-core.
           &gt; Unable to load Maven meta-data from https://google.bintray.com/exoplayer/io/grpc/grpc-core/maven-metadata.xml.
              &gt; Could not get resource 'https://google.bintray.com/exoplayer/io/grpc/grpc-core/maven-metadata.xml'.
                 &gt; Could not GET 'https://google.bintray.com/exoplayer/io/grpc/grpc-core/maven-metadata.xml'. Received status code 502 from server: Bad Gateway
  
  * Try:
  Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.
  
  * Get more help at https://help.gradle.org
  
  BUILD FAILED in 5s
  </code></pre>