Revert "Twitter-oss: update OSS libraries post-release to 21.9.0"

Problem:

Sonatype requires a javadoc jar, even if empty to release.

Solution / Result:

Revert the post-release commit to act as the new SHA to which
will be released. This SHA will come after D724170 which doesn't
skip the creation of the empty util javadoc JAR for Scala 3.

JIRA Issues: CSL-11162

Differential Revision: https://phabricator.twitter.biz/D724302

Twitter-oss: Prepare OSS libraries for release 21.6.0

Problem

We want to release the next versions of our Twitter OSS libraries 21.6.0
 - util
 - scrooge
 - finagle
 - twitter-server
 - finatra

Solution

Prepare libraries for their next releases.

Differential Revision: https://phabricator.twitter.biz/D692183

Twitter-oss: Prepare OSS libraries for release 21.5.0

Problem

We want to release the next versions of our Twitter OSS libraries 21.5.0
 - util
 - scrooge
 - finagle
 - twitter-server
 - finatra

Solution

Prepare libraries for their next releases.

Differential Revision: https://phabricator.twitter.biz/D677481

Twitter-oss: Prepare OSS libraries for release 21.4

Problem

We want to release the next versions of our Twitter OSS libraries 21.4.0
 - util
 - scrooge
 - finagle
 - twitter-server
 - finatra

Solution

Prepare libraries for their next releases.

JIRA Issues: CSL-10889

Differential Revision: https://phabricator.twitter.biz/D658986

Twitter-oss: Prepare OSS libraries for release 21.3.0

Problem/Solution

Let's move the `dodo` CHANGELOG to RST so that it gets
updated on each release and prep the release for 21.3.0.

JIRA Issues: CSL-10793

Differential Revision: https://phabricator.twitter.biz/D641843

Twitter-oss: Prepare OSS libraries for release 21.2.0

Problem

We want to release the next versions of our Twitter OSS libraries 21.2.0
 - util
 - scrooge
 - finagle
 - twitter-server
 - finatra

Solution

Prepare libraries for their next releases.

Differential Revision: https://phabricator.twitter.biz/D615824

Twitter-oss: Prepare OSS libraries for release 21.1.0

Problem

We want to release the next versions of our Twitter OSS libraries 21.1.0
 - util
 - scrooge
 - finagle
 - twitter-server
 - finatra

Solution

Prepare libraries for their next releases.

Differential Revision: https://phabricator.twitter.biz/D602794

Twitter-oss: Prepare OSS libraries for release 20.12.0

Problem

We want to release the next versions of our Twitter OSS libraries 20.12.0
 - util
 - scrooge
 - finagle
 - twitter-server
 - finatra

Solution

Prepare libraries for their next releases.

JIRA Issues: CSL-10389

Differential Revision: https://phabricator.twitter.biz/D589851

Twitter-oss: Prepare OSS libraries for release 20.10.0

Problem

We want to release the next versions of our Twitter OSS libraries 20.10.0
 - util
 - scrooge
 - finagle
 - twitter-server
 - finatra

Solution

Prepare libraries for their next releases.

JIRA Issues: CSL-10323

Differential Revision: https://phabricator.twitter.biz/D571081

Twitter-oss: Prepare OSS libraries for release 20.9.0

Problem

We want to release the next versions of our Twitter OSS libraries 20.9.0
 - util
 - scrooge
 - finagle
 - twitter-server
 - finatra

Solution

Prepare libraries for their next releases.

JIRA Issues: CSL-10167

Differential Revision: https://phabricator.twitter.biz/D553327