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_ipmi_redfish_user.robot b/redfish/account_service/test_ipmi_redfish_user.robot
index 02a95c9..9edc497 100644
--- a/redfish/account_service/test_ipmi_redfish_user.robot
+++ b/redfish/account_service/test_ipmi_redfish_user.robot
@@ -285,7 +285,7 @@
     Run Keyword If  '${privilege}' != '0'
     ...  Set Channel Access  ${random_userid}  ipmi=on privilege=${privilege}
 
-    [Return]  ${random_username}  ${random_userid}
+    RETURN  ${random_username}  ${random_userid}
 
 
 Delete Users Via Redfish
@@ -336,4 +336,4 @@
         Exit For Loop If  ${is_empty} == ${True}
     END
     Run Keyword If  '${jj}' == '299'  Fail  msg=A free user ID could not be found.
-    [Return]  ${random_userid}
+    RETURN  ${random_userid}