Add a notice to the release testing rotation file

[stefanobaghino-da]

Reminds people adding new users to the rotation that they should also
be added to DACH-NY/daml-language-ad-hoc to have a box in the cloud
for Windows testing.

Adds the possibility of adding comments at the beginning of the rotation file.

changelog_begin
changelog_end

Pull Request Checklist

• Read and understand the contribution guidelines
• Include appropriate tests
• Set a descriptive title and thorough description
• Add a reference to the issue this PR will solve, if appropriate
• Include changelog additions in one or more commit message bodies between the CHANGELOG_BEGIN and CHANGELOG_END tags
• Normal production system change, include purpose of change in description

NOTE: CI is not automatically run on non-members pull-requests for security
reasons. The reviewer will have to comment with /AzurePipelines run to
trigger the build.

[stefanobaghino-da]

Testing

I manually tested that awk '/^[^#]/ {print $1}' release/rotation | head -n 1 and awk '/^[^#]/ {print $2}' release/rotation | head -n 1 print respectively the first and second field from the file, excluding comments.

I manually tested rotate by copying and pasting it in my shell and running it and it produces the following diff, which looks sane:

@@ -1,7 +1,6 @@
 # If you are adding someone to the rotation, remember to also give them permission
 # to access an ad-hoc machine for Windows testing. This can be done by opening a PR
 # like the following: https://github.com/DACH-NY/daml-language-ad-hoc/pull/37
-U02DCD54R28 adriaanm-da
 U7BSDJUJX S11001001
 U011H6KFYPN sofiafaro-da
 U026PEZLTPX akshayshirahatti-da
@@ -15,3 +14,4 @@ U02DAFHFXUN akrmn
 UEHLS0JUB cocreature
 UEHSF89AQ garyverhaegen-da
 UD3MUK6TA stefanobaghino-da
+U02DCD54R28 adriaanm-da

[garyverhaegen-da]

Seeing those two diffs side-by-side now, do you think it'd be worth to move that to a function in bash-lib?

[garyverhaegen-da]

Commented on the second one but there are actually 5 instances, so I think we're definitely past the threshold where a function makes sense. I can do it as a separate PR if you want, though. No need to block this one on that.

[stefanobaghino-da]

Yes, please. I'll merge this. 🙇🏻

[garyverhaegen-da]

Thanks!