Add activity options to the pending activity info (#586)

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<!-- Describe what has changed in this PR -->
**What changed?**
Add activity options to the pending activity info

<!-- Tell your future self why have you made these changes -->
**Why?**
If activity options where changed - there is no "official" way to users
to know what are the current options.
UI should display current options, so we will provide them as a part of
DescribeWorfklow response.
Thus we add activity options to the pending activity info, which will be
a part of DescribeWorfklow response.

<!-- Are there any breaking changes on binary or code level? -->
**Breaking changes**
No

Author: ychebotarev

openapi/openapiv2.json

@@ -11771,6 +11771,10 @@
         },
         "pauseInfo": {
           "$ref": "#/definitions/PendingActivityInfoPauseInfo"
+        },
+        "activityOptions": {
+          "$ref": "#/definitions/v1ActivityOptions",
+          "description": "Current activity options. May be different from the one used to start the activity."
         }
       }
     },

openapi/openapiv3.yaml

@@ -8859,6 +8859,10 @@ components:
           description: Priority metadata
         pauseInfo:
           $ref: '#/components/schemas/PendingActivityInfo_PauseInfo'
+        activityOptions:
+          allOf:
+            - $ref: '#/components/schemas/ActivityOptions'
+          description: Current activity options. May be different from the one used to start the activity.
     PendingActivityInfo_PauseInfo:
       type: object
       properties:

temporal/api/workflow/v1/message.proto

@@ -14,6 +14,7 @@ import "google/protobuf/empty.proto";
 import "google/protobuf/timestamp.proto";
 import "google/protobuf/field_mask.proto";
 
+import "temporal/api/activity/v1/message.proto";
 import "temporal/api/enums/v1/common.proto";
 import "temporal/api/enums/v1/event_type.proto";
 import "temporal/api/enums/v1/workflow.proto";
@@ -322,6 +323,9 @@ message PendingActivityInfo {
     }
 
     PauseInfo pause_info = 23;
+
+    // Current activity options. May be different from the one used to start the activity.
+    temporal.api.activity.v1.ActivityOptions activity_options = 24;
 }
 
 message PendingChildExecutionInfo {