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/redfish/systems/eventlog/test_esel.robot b/redfish/systems/eventlog/test_esel.robot
index 84d025d..d1947e3 100644
--- a/redfish/systems/eventlog/test_esel.robot
+++ b/redfish/systems/eventlog/test_esel.robot
@@ -167,7 +167,7 @@
     [Documentation]  Run the IPMI command and return the output.
     [Arguments]    ${args}
     ${output_1}=    Execute Command   /tmp/ipmitool -I dbus raw ${args}
-    [Return]    ${output_1}
+    RETURN    ${output_1}
 
 
 Check IPMI OEMpartialadd Reject
@@ -176,7 +176,7 @@
     Login To OS Host  ${OS_HOST}  ${OS_USERNAME}  ${OS_PASSWORD}
     ${stdout}  ${stderr}  ${output_2}=  Execute Command  ipmitool raw ${args}
     ...        return_stdout=True  return_stderr=True  return_rc=True
-    [Return]  ${stderr}
+    RETURN  ${stderr}
 
 
 Test Setup Execution
@@ -213,7 +213,7 @@
     ${stdout}  ${stderr}  ${output_3}=  Execute Command  ipmitool raw ${args}
     ...         return_stdout=True  return_stderr=True  return_rc=True
     Should Be Equal  ${output_3}  ${0}  msg=${stderr}
-    [Return]  ${stderr}
+    RETURN  ${stderr}
 
 
 Event Log Should Exist
diff --git a/redfish/systems/eventlog/test_event_logging.robot b/redfish/systems/eventlog/test_event_logging.robot
index 498f943..8aa676b 100644
--- a/redfish/systems/eventlog/test_event_logging.robot
+++ b/redfish/systems/eventlog/test_event_logging.robot
@@ -435,7 +435,7 @@
       Append To List  ${error_ids}  ${error_id}
     END
 
-    [Return]  ${error_ids}
+    RETURN  ${error_ids}
 
 
 Event Log Should Not Exist