Broken link to .travis.yml example file in docs

[cac03]

Hello,

the General Docker requirements page refers to a non-existent .travis.yml file in the repository. See the "Linux - Travis CI" row and the "Known issues / tips" column

The file has been removed in the 5d87f61 commit

[kiview]

Hi @cac03,
thanks for bringing this to our attention, you are completely right. I think the Travis part should be completely removed from General Docker requirements page. We can think about adding it to the Continous Integration section if we still feel the need to have this documented.

[cac03]

@kiview, thanks for your response

Yes, I wasn't sure what exactly would be appropriate to fix this.
I've created a #4374 PR to remove the "Travis CI" part from the page

[rnorth]

@kiview I'm not so sure that removing Travis CI entirely is the right thing just because we don't have an example configuration to point people towards...

I'd say that the table certainly needs a refresh, though.