chore(tracer): use hard coded version for the tracer

[christophe-papazian]

Following the october 17 meeting in Paris, this is a proposition to replace computation of the version using setuptools with a static file.

Checklist

• [x] Change(s) are motivated and described in the PR description.
• [x] Testing strategy is described if automated tests are not included in the PR.
• [x] Risk is outlined (performance impact, potential for breakage, maintainability, etc).
• [x] Change is maintainable (easy to change, telemetry, documentation).
• [x] Library release note guidelines are followed. If no release note is required, add label changelog/no-changelog.
• [x] Documentation is included (in-code, generated user docs, public corp docs).
• [x] Backport labels are set (if applicable)

Reviewer Checklist

• [ ] Title is accurate.
• [ ] No unnecessary changes are introduced.
• [ ] Description motivates each change.
• [ ] Avoids breaking API changes unless absolutely necessary.
• [ ] Testing strategy adequately addresses listed risk(s).
• [ ] Change is maintainable (easy to change, telemetry, documentation).
• [ ] Release note makes sense to a user of the library.
• [ ] Reviewer has explicitly acknowledged and discussed the performance implications of this PR as reported in the benchmarks PR comment.
• [ ] Backport labels are set in a manner that is consistent with the release branch maintenance policy
• [ ] If this PR touches code that signs or publishes builds or packages, or handles credentials of any kind, I've requested a review from @DataDog/security-design-and-guidance.
• [ ] This PR doesn't touch any of that.

[pr-commenter[bot]]

Benchmarks

Benchmark execution time: 2023-10-20 12:32:01

Comparing candidate commit 411c88e2c6f32c9a8449499261d4a41b4ffabbc1 in PR branch christophe-papazian/fix_version_static_file with baseline commit 8ce00088f7f8025e2851eea60eb37862c259cfdd in branch 2.x.

Found 0 performance improvements and 0 performance regressions! Performance is the same for 90 metrics, 0 unstable metrics.

[romainkomorn-exdatadog]

I think I'd go for something where the file containing the version numbers is standalone, and version.py reads it.

My thinking here is that it'd be good to make that file something machine-readable that can be read and updated by the release script.