doc: elevate diagnostic report to tier1

[gireeshpunathil]

diagnostic WG recommends that: diagnostic report qualifies for all the criteria for being in tier1. Classify it as such.

checklist:

criteria	status
The maintainers of the tool must remain responsive when there are problems	tool is part of the core, so maintainers are node core collaborators itself
The tool must be actively used by the ecosystem	evidence of usage in the field - through core and help repo issues, as well as in person feedback in collab summit 2019 montreal
The tool must be heavily depended on	subjective, but report is being established as a unique FFDC capability that helped many issues so far
The tool must have a guide or other documentation in the Node.js GitHub organization or website	API guide exists part of the org, and several external documentations
The tool must be working on all supported platforms	Achieved, functional on all platforms where Node.js is supported
The tool must only be using APIs exposed by Node.js as opposed to its dependencies; and the tool must be open source	Achieved

• this is the first time a tool is potentially entering the tier1 status. As per the documented process, the most notable one is: A release will not be shipped if the test suite for the tool/API is not green. (this page, second para). So alerting the release team for their awareness and / or review.

• @richardlau raised a point about retaining node-report in the unclassified list. While diagnostic report is replacement of node-report in principle, in reality both need to co-exist until v10.x goes out of support (04/21). I am fine in either way, but my opinion is to replace node-report in the list - node-report is an npm module, so its support tier status listing in core as unclassified or absence of it may not be too critical to the ecosystem.

Refs: nodejs/diagnostics#369
/cc @nodejs/releasers
/cc @nodejs/diagnostics
/cc @nodejs/tooling

Checklist

• make -j4 test (UNIX), or vcbuild test (Windows) passes
• tests and/or benchmarks are included
• documentation is changed or added
• commit message follows commit guidelines

[richardlau]

I would rather either keep the npm node-report module as unclassified or moved to tier 4.

[mhdawson]

I would move it to tier unclassified.

[gireeshpunathil]

@richardlau @mhdawson - reverted the case of node-report, PTAL!

[richardlau]

* this is the first time a tool is potentially entering the `tier1` status. As per the documented process, the most notable one is: `A release will not be shipped if the test suite for the tool/API is not green.` (this page, second para). So alerting the release team for their awareness and / or review.

For diagnostics report, since it's in core the tests for it are part of the regular test CI so no concerns there.

I'm not sure the Release WG has been consulted on the broader Tier requirements. The only mechanism we have of running tests for releases is either (a) tests that exist in core and are therefore run as part of regular/nightly CI, or (b) CITGM (which can only test npms). I'm hesitant to place more requirements in the future on @nodejs/releasers.

[mhdawson]

LGTM

[mmarchini]

@richardlau agreed, for those tools to be tier 1 they need to be tested either on Node.js core or as part of CITGM. We should add this as a pre-requirement for Tier 1.

[mcollina]

lgtm

[jasnell]

Landed in 6ad65ae