Robot Framework 7.0 changes

Update robot code syntax overall in the repo

Changes:
   - Update the requirement.txt package version for robot
   - The '[Return]' setting is deprecated.
      Use the 'RETURN' statement instead.
   - Singular section headers like '*** Test Case ***'
     are deprecated. Use plural format like
     '*** Test Cases ***' instead.
   - Singular section headers like '*** Variable ***'
     are deprecated

Tested:
   - Ran from sandbox with the version
     $ robot --version
     Robot Framework 7.0 (Python 3.10.12 on linux)

     and also tested on latest python version

     Robot Framework 7.0 (Python 3.11.9 on linux)

Change-Id: I54e85f9d799556c63b9a39f79483f83e9b980768
Signed-off-by: George Keishing <gkeishin@in.ibm.com>
diff --git a/pldm/test_pldm_platform.robot b/pldm/test_pldm_platform.robot
index 333ede7..fc68fb5 100644
--- a/pldm/test_pldm_platform.robot
+++ b/pldm/test_pldm_platform.robot
@@ -101,7 +101,7 @@
     ...  ELSE  Fail  msg="Unknown PDR Type is received"
 
     Should be equal as strings  ${pldm_output['recordHandle']}  ${record_handle}
-    [Return]  ${pldm_output['nextRecordHandle']}
+    RETURN  ${pldm_output['nextRecordHandle']}
 
 Verify SetStateEffecterStates For Effecter States
     [Documentation]  Verify set state effecter states for given input effecter states.