Fix broken link in to Cirque documentation

[neonsoftware]

Problem

The user, when cliicking on the link to the Cirque's README documentation page, was landing on a 404 Github page, due to an invalid relative link.

Summary of Changes

The link is fixes, and the documentation navigation is now working correctly.

[neonsoftware]

Status
The GIthub doxygen workflow reported the following issue:
/home/runner/work/connectedhomeip/connectedhomeip/docs/README.md:9: error: unexpected token TK_EOF as the argument of ref (warning treated as error, aborting now)

Although launching locally ./scripts/helpers/doxygen.sh the doxignen generation was successful and the link working.

Action
Investigating why the doxygen is failing on the Github workflow (and not locally). I have re-uploaded the commit with a freshly re-modified line, in case it was an issue with encoding.

[bzbarsky-apple]

Investigating why the doxygen is failing on the Github workflow (and not locally)

What version of doxygen are you running locally? This looks a lot like doxygen/doxygen#8130 which was just fixed a few months ago. Fix is in doxygen 1.9.0, but our containers are running doxygen 1.8.17, afaict.

[neonsoftware]

Hi @bzbarsky-apple,
Spot on. I run 1.9.1 locally.
And, yes, Github offers up to Ubuntu 20-04 on workflows, while 1.9.x is only from ubuntu 21-04.
It might be that.

Before I make any correction, what do you think, or any other of the project of course, would be the best way forward ?

• option A: in the Github workflow, I will add a temporary step, with bash doing if(doxygen version < 1.9.x) { install doxygen from ubuntu 21-04 }, marking such workflow step with a comment, capital letters, "this step can be removed once default doxygen version will be 1.9.x"
• option B: as option A, still manually upgrading doxygen in the workflow, but better, looking forward any idea or suggestion
• option C: asking the doxygen project a backport of the fix to 1.8.17+ and putting this issue on hold until available
• option D: none of the above and deleting this issue
• option E: any other option that I might have not considered yet, let me know

Considering that with option C and D the documentation has broken links in this phase of adoption.

Let me know, cheers, have an outstanding week, F

[bzbarsky-apple]

My gut feeling is that if we can do the doxygen update in our container in general, not on a per-workflow basis, that would be ideal. I guess that's option B, right?

@woody-apple How feasible is that?

[electrocucaracha]

I have created this PR to automate the validation of broken links, hopefully that helps to early detect these issues.

[neonsoftware]

@electrocucaracha great.

[woody-apple]

/rebase