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/task_service/test_tasks_service.robot b/redfish/task_service/test_tasks_service.robot
index 73d959b..27f7e53 100644
--- a/redfish/task_service/test_tasks_service.robot
+++ b/redfish/task_service/test_tasks_service.robot
@@ -275,4 +275,4 @@
     # Convert the date format to %m/%d/%Y %H:%M:%S
     ${date}=  Convert Date  ${date}  date_format=%b %d %H:%M:%S %Y  result_format=%m/%d/%Y %H:%M:%S  exclude_millis=True
 
-    [Return]   ${date}
+    RETURN   ${date}