Baseline: e2ae73fe16cbedf095b9e6d5687b06ecf765d794

Cherry picks:

   + 0fdb485421f9d134f11103a36c48182769fb40d3:
     Automated rollback of commit
     f2230d8494e70f02b1e4fb082fcf8550aa684a40.
   + 1f52e9a58dd814f203797c5fbab44d9f4d53a43c:
     Support rolling releases in Bazel release scripts.
   + 2f72244183c8c3de722ff1d9e8b0b745d12cd528:
     Fix syntax error in Bazel release scripts
   + 4ef9c566c861848fef7907cf07a6e7d9d15cee7a:
     Fix location of -prerelease option
   + a6dfd927c58c63275159858ac661a9b669594a0c:
     Add --experimental_shadowed_action to graveyard options for all
     commands.

Important changes:

  - If all strategies of one branch (the local or remote execution
    branch) of the `dynamic` strategy fail to even accept (via the
    response they give from `canExec`) the action, `dynamic` will now
    try to see if the other branch can accept it. (Trying to run it
    and it failing will still cause a failure if it was the first
    result, this is about strategies claiming they can't even try the
    action)

This release contains contributions from many people at Google, as well as Benedek Thaler.