[marl] Repoint HEAD_REF to main

[ben-clayton]

marl's default branch has been renamed from master to main.

See google/marl#153 for more details.

[PhoebeHui]

@ben-clayton, thanks for your PR!

Could you update the Version to '2020-05-21-1' in CONTROL file?

[ben-clayton]

Could you update the Version to '2020-05-21-1' in CONTROL file?

My understanding is that this should be adjusted if the package version / revision is actually changing - which in this case it is not. The SHA referenced is the same as before, I'm simply updating HEAD_REF to use the new name for the default branch, which is a direct mirror (same SHAs) of the old master branch.

I could be wrong though, so please let me know if I'm talking rubbish. :)

[PhoebeHui]

@ben-clayton, sorry for the confuse.

If the port has been modified, we append a -N to distinguish the versions, it's not relate to SHA.

[ghost]

Thank you for your submission, we really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.

❌ ben-clayton sign now
_{You have signed the CLA already but the status is still pending? Let us recheck it.}

[ben-clayton]

I'm afraid I have to go through some red-tape to sign this CLA (not sure why this is check is kicking in only now).
If someone else wants to make this change on my behalf, I'd very much appreciate it.