upgrade CI actions · apache/pekko-http@9100092

Node.js 16 actions are deprecated. Please update the following actions to use Node.js 20: actions/cache@v3, actions/upload-artifact@v3. For more information see: https://github.blog/changelog/2023-09-22-github-actions-transitioning-from-node-16-to-node-20/.

Compile everything: parsing/src/main/scala-2/org/apache/pekko/http/ccompat/pre213macro.scala#L17

Unused import

Compile everything: parsing/src/main/scala-2/org/apache/pekko/http/ccompat/since213macro.scala#L17

Unused import

Compile everything: http-scalafix/scalafix-rules/src/main/scala/org/apache/pekko/http/fix/MigrateToServerBuilder.scala#L31

method args in trait Apply is deprecated: 4.6.0

Compile everything: http-scalafix/scalafix-rules/src/main/scala/org/apache/pekko/http/fix/MigrateToServerBuilder.scala#L45

method args in trait Apply is deprecated: 4.6.0

Compile everything: http-core/src/main/scala/org/apache/pekko/http/impl/engine/client/PoolInterface.scala#L232

parameter ec in method shutdown is never used

Compile everything: http-core/src/main/scala/org/apache/pekko/http/scaladsl/model/HttpEntity.scala#L666

method getFirst in class Attributes is deprecated (since Akka 2.5.7): Attributes should always be most specific, use get[T]