Update versions of libraries in poetry.

PATCH bump source-firebase-realtime-database version to 0.1.21
Build source-firebase-realtime-database docker image for platform(s) linux/amd64, linux/arm64
Get dependency updates
Create or update pull request on Airbyte repository
Add changelog entry

Author: airbyteio

airbyte-integrations/connectors/source-firebase-realtime-database/metadata.yaml

@@ -5,7 +5,7 @@ data:
   connectorSubtype: database
   connectorType: source
   definitionId: acb5f973-a565-441e-992f-4946f3e65662
-  dockerImageTag: 0.1.20
+  dockerImageTag: 0.1.21
   dockerRepository: airbyte/source-firebase-realtime-database
   githubIssueLabel: source-firebase-realtime-database
   license: MIT