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/account_service/test_user_account.robot b/redfish/account_service/test_user_account.robot
index 5c50698..40d82b1 100644
--- a/redfish/account_service/test_user_account.robot
+++ b/redfish/account_service/test_user_account.robot
@@ -622,7 +622,7 @@
     Run Keyword And Ignore Error  Redfish.Logout
 
     ${status}=  Run Keyword And Return Status  Redfish.Login  ${username}  ${password}
-    [Return]  ${status}
+    RETURN  ${status}
 
 
 Redfish Create And Verify User