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_bmc_ipv6.robot b/redfish/managers/test_bmc_ipv6.robot
index 2ddaacd..04853cf 100644
--- a/redfish/managers/test_bmc_ipv6.robot
+++ b/redfish/managers/test_bmc_ipv6.robot
@@ -193,7 +193,7 @@
     ${resp}=  Redfish.Get  ${REDFISH_NW_ETH_IFACE}${active_channel_config['${CHANNEL_NUMBER}']['name']}
 
     @{ipv6_network_configurations}=  Get From Dictionary  ${resp.dict}  IPv6StaticAddresses
-    [Return]  @{ipv6_network_configurations}
+    RETURN  @{ipv6_network_configurations}
 
 
 Verify IPv6 And PrefixLength