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/managers/test_multiple_interfaces.robot b/redfish/managers/test_multiple_interfaces.robot
index 90bd68d..011cd04 100644
--- a/redfish/managers/test_multiple_interfaces.robot
+++ b/redfish/managers/test_multiple_interfaces.robot
@@ -195,7 +195,7 @@
     ${resp}=  Redfish.Get  ${REDFISH_NW_ETH_IFACE}${ethernet_interface}
 
     @{network_configurations}=  Get From Dictionary  ${resp.dict}  IPv4StaticAddresses
-    [Return]  @{network_configurations}
+    RETURN  @{network_configurations}
 
 
 Suite Setup Execution
@@ -255,7 +255,7 @@
 
     ${rc}  ${output}=  Run And Return Rc And Output  ${cmd_prefix} -H ${host} ${sub_cmd}
     Should Be Equal As Strings  ${rc}  0
-    [Return]  ${output}
+    RETURN  ${output}
 
 
 Install Certificate Via Redfish And Verify
@@ -293,4 +293,4 @@
     ${bmc_cert_content}=  Run Keyword If  '${expected_status}' == 'ok'  redfish_utils.Get Attribute
     ...  ${certificate_uri}/${cert_id}  CertificateString
     Run Keyword If  '${expected_status}' == 'ok'  Should Contain  ${cert_file_content}  ${bmc_cert_content}
-    [Return]  ${cert_id}
+    RETURN  ${cert_id}