Robotframework request package upgrade changes

Current working package version
   robotframework-requests            0.7.2

To Test:
      pip3 install robotframework-requests -U
                 or
      # Once this commit is merged.
      pip3 install -r requirements.txt

      Version latest:
      robotframework-requests         0.9.3

Refer Documentation:
   https://marketsquare.github.io/robotframework-requests/doc/RequestsLibrary.html

What is not changed:
     - The test cases under directory tests/ is not modified and is
       deprecated but you can continue using it with older package
       and configuration using

       git clone -b v3.0-stable https://github.com/openbmc/openbmc-test-automation

Tested:
      Upstream HW_CI test list, firmware code update and few other
      test suite like ipmi, certificate, dumps, ffdc and redfish
      test suites.

Note: I have not tested end to end, so it is likely there could be
      grey areas where it could fail but should be minor w.r.t
      response data format.

Resolves:  openbmc/openbmc-test-automation#2105

Change-Id: Ie03b25ff88948bcccb09e9d82f8da86e28c92697
Signed-off-by: George Keishing <gkeishin@in.ibm.com>
diff --git a/lib/certificate_utils.robot b/lib/certificate_utils.robot
index 7f14bf3..9930aac 100755
--- a/lib/certificate_utils.robot
+++ b/lib/certificate_utils.robot
@@ -30,14 +30,13 @@
     ...  X-Auth-Token=${XAUTH_TOKEN}
     Set To Dictionary  ${kwargs}  headers  ${headers}
 
-    ${ret}=  Post Request  openbmc  ${uri}  &{kwargs}
-    ${content_json}=  To JSON  ${ret.content}
-    ${cert_id}=  Set Variable If  '${ret.status_code}' == '${HTTP_OK}'  ${content_json["Id"]}  -1
+    ${resp}=  POST On Session  openbmc  ${uri}  &{kwargs}  expected_status=any
+    ${cert_id}=  Set Variable If  '${resp.status_code}' == '${HTTP_OK}'  ${resp.json()["Id"]}  -1
 
     Run Keyword If  '${status}' == 'ok'
-    ...  Should Be Equal As Strings  ${ret.status_code}  ${HTTP_OK}
+    ...  Should Be Equal As Strings  ${resp.status_code}  ${HTTP_OK}
     ...  ELSE IF  '${status}' == 'error'
-    ...  Should Be Equal As Strings  ${ret.status_code}  ${HTTP_INTERNAL_SERVER_ERROR}
+    ...  Should Be Equal As Strings  ${resp.status_code}  ${HTTP_INTERNAL_SERVER_ERROR}
 
     Delete All Sessions