Add web identity token support to cloudwatch logs provisioner (#2197)

Author: jefchien

go.mod

@@ -152,34 +152,31 @@ extensions:
               from_context: aws.log.stream.name
               key: x-aws-log-stream
     sigv4auth/logs:
-        assume_role:
-            arn: ${CWAGENT_ROLE_ARN}
-            sts_region: us-west-2
+        assume_role: {}
         imds_retries: 1
         max_retries: 2
         num_workers: 8
         region: us-west-2
         request_timeout_seconds: 30
+        role_arn: ${CWAGENT_ROLE_ARN}
         service: logs
     sigv4auth/monitoring:
-        assume_role:
-            arn: ${CWAGENT_ROLE_ARN}
-            sts_region: us-west-2
+        assume_role: {}
         imds_retries: 1
         max_retries: 2
         num_workers: 8
         region: us-west-2
         request_timeout_seconds: 30
+        role_arn: ${CWAGENT_ROLE_ARN}
         service: monitoring
     sigv4auth/xray:
-        assume_role:
-            arn: ${CWAGENT_ROLE_ARN}
-            sts_region: us-west-2
+        assume_role: {}
         imds_retries: 1
         max_retries: 2
         num_workers: 8
         region: us-west-2
         request_timeout_seconds: 30
+        role_arn: ${CWAGENT_ROLE_ARN}
         service: xray
 processors:
     attributestocontext/opentelemetry: