feat(source-mailchimp): add oauth_connector_input_specification for declarative OAuth (#75576)

Author: lazebnyi

airbyte-integrations/connectors/source-mailchimp/manifest.yaml

@@ -4792,6 +4792,19 @@ spec:
       - auth_type
     predicate_value: oauth2.0
     oauth_config_specification:
+      oauth_connector_input_specification:
+        consent_url: "https://login.mailchimp.com/oauth2/authorize?{{client_id_param}}&{{redirect_uri_param}}&response_type=code&{{state_param}}"
+        access_token_url: "https://login.mailchimp.com/oauth2/token"
+        access_token_headers:
+          Content-Type: "application/x-www-form-urlencoded"
+        access_token_params:
+          grant_type: "authorization_code"
+          code: "{{ auth_code_value }}"
+          client_id: "{{ client_id_value }}"
+          client_secret: "{{ client_secret_value }}"
+          redirect_uri: "{{ redirect_uri_value }}"
+        extract_output:
+          - access_token
       complete_oauth_output_specification:
         type: object
         additionalProperties: false

airbyte-integrations/connectors/source-mailchimp/metadata.yaml

@@ -11,7 +11,7 @@ data:
   connectorSubtype: api
   connectorType: source
   definitionId: b03a9f3e-22a5-11eb-adc1-0242ac120002
-  dockerImageTag: 2.1.21
+  dockerImageTag: 2.1.22
   dockerRepository: airbyte/source-mailchimp
   documentationUrl: https://docs.airbyte.com/integrations/sources/mailchimp
   externalDocumentationUrls:

docs/integrations/sources/mailchimp.md

@@ -126,6 +126,7 @@ Now that you have set up the Mailchimp source connector, check out the following
 
 | Version | Date       | Pull Request                                             | Subject                                                                   |
 |--------|------------|----------------------------------------------------------|---------------------------------------------------------------------------|
+| 2.1.22 | 2026-04-01 | [75576](https://github.com/airbytehq/airbyte/pull/75576) | Add `oauth_connector_input_specification` for declarative OAuth |
 | 2.1.21 | 2026-03-31 | [75803](https://github.com/airbytehq/airbyte/pull/75803) | Update dependencies |
 | 2.1.20 | 2026-03-24 | [74579](https://github.com/airbytehq/airbyte/pull/74579) | Update dependencies |
 | 2.1.19 | 2026-03-03 | [74155](https://github.com/airbytehq/airbyte/pull/74155) | Update dependencies |