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/network/test_network_nping.robot b/network/test_network_nping.robot
index f9d0874..7155cc9 100644
--- a/network/test_network_nping.robot
+++ b/network/test_network_nping.robot
@@ -59,7 +59,7 @@
     ${rc}  ${output}  Run And Return RC And Output  ${cmd_buff}
     Should Be Equal As Integers  ${rc}  0  msg=Command execution failed.
     ${packet_loss}  Get Packet Loss  ${host}  ${output}
-    [Return]  ${packet_loss}
+    RETURN  ${packet_loss}
 
 Get Packet Loss
     [Documentation]  Check packet loss percentage.
@@ -84,4 +84,4 @@
 
     ${summary}=  Get Lines Containing String  ${traffic_details}  Rcvd:
     Log To Console  \nPacket loss summary on ${host}\n*********************
-    [Return]  ${summary}
+    RETURN  ${summary}