change mgmt_ipv4/6 to mgmt-ipv4/6

[steiler]

Besides changing dash to underscore for ipv{4,6}_subnet via #1365.
I think the mgmt_ipv4/6 config stanza is the last remaining underscore topology setting.
I think, it would make sense to bundle this and #1365 in a single release, to have such breaking change just once.

This will in then in my view be enough to close #749

[hellt]

Yes, these changes definitely must go together.
Besides that, I think we need to create a special error message notifying people to check release notes when unmarshalling error happens for unrecognized fields

[steiler]

That would be here then.
https://github.com/srl-labs/containerlab/blob/main/clab/file.go#L76
What do you propose as the message to show?

[hellt]

@steiler

Failed to read the topology definition file. Consult with release notes to see if any fields were changed/removed.

[hellt]

PS. Currently I already see that this message is emitted:

 dclab des -c -t private/linux.clab.yml
Error: failed to read topology file: yaml: unmarshal errors:
  line 5: field ipv4-subnet not found in type types.MgmtNet
  line 6: field ipv4-range not found in type types.MgmtNet

[codecov]

Codecov Report

Merging #1370 (76ef72d) into main (ccd6e3b) will increase coverage by 0.00%.
The diff coverage is 0.00%.

@@           Coverage Diff           @@
##             main    #1370   +/-   ##
=======================================
  Coverage   20.82%   20.82%           
=======================================
  Files          57       58    +1     
  Lines        6286     6333   +47     
=======================================
+ Hits         1309     1319   +10     
- Misses       4856     4891   +35     
- Partials      121      123    +2     

Impacted Files	Coverage Δ
clab/file.go	54.54% <0.00%> (-2.60%)	⬇️
types/node_definition.go	17.24% <ø> (ø)

... and 4 files with indirect coverage changes