docs: add readme pointer to versioning documentation

[emmettbutler]

This change puts the version-maintenance policy in a more discoverable location to reduce confusion about what versions of ddtrace are maintained.

Checklist

• PR author has checked that all the criteria below are met
• The PR description includes an overview of the change
• The PR description articulates the motivation for the change
• The change includes tests OR the PR description describes a testing strategy
• The PR description notes risks associated with the change, if any
• Newly-added code is easy to change
• The change follows the library release note guidelines
• The change includes or references documentation updates if necessary
• Backport labels are set (if applicable)

Reviewer Checklist

• Reviewer has checked that all the criteria below are met
• Title is accurate
• All changes are related to the pull request's stated goal
• Avoids breaking API changes
• Testing strategy adequately addresses listed risks
• Newly-added code is easy to change
• Release note makes sense to a user of the library
• If necessary, author has 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

[github-actions]

CODEOWNERS have been resolved as:

README.md                                                               @DataDog/python-guild @DataDog/apm-core-python

[github-actions]

Bootstrap import analysis

Comparison of import times between this PR and main.

Summary

The average import time in this PR is: 237 ± 2 ms.

The average import time in main is: 239 ± 2 ms.

The import time difference between this PR and main is: -1.64 ± 0.09 ms.

Import time breakdown

The following import paths have grown:

ddtrace.auto 0.021 ms (0.01%)

ddtrace.bootstrap.sitecustomize 0.021 ms (0.01%)

ddtrace.bootstrap.preload 0.021 ms (0.01%)

ddtrace.internal.products 0.021 ms (0.01%)

ddtrace.settings.dynamic_instrumentation 0.021 ms (0.01%)

The following import paths have shrunk:

ddtrace.auto 1.924 ms (0.81%)

ddtrace.bootstrap.sitecustomize 1.278 ms (0.54%)

ddtrace.bootstrap.preload 1.278 ms (0.54%)

ddtrace.internal.products 1.278 ms (0.54%)

ddtrace.internal.remoteconfig.client 0.630 ms (0.27%)

ddtrace 0.646 ms (0.27%)

[pr-commenter]

Benchmarks

Benchmark execution time: 2025-03-21 15:58:33

Comparing candidate commit 0fa2d45 in PR branch emmett.butler/versions-readme with baseline commit ce2d69d in branch main.

Found 5 performance improvements and 0 performance regressions! Performance is the same for 493 metrics, 2 unstable metrics.

scenario:iast_aspects-format_map_aspect

• 🟩 execution_time [-551.496ns; -484.561ns] or [-9.852%; -8.656%]

scenario:iast_aspects-ospathbasename_aspect

• 🟩 execution_time [-425.553ns; -369.424ns] or [-11.478%; -9.964%]

scenario:iast_aspects-ospathdirname_aspect

• 🟩 execution_time [-708.853ns; -642.543ns] or [-16.078%; -14.574%]

scenario:iast_aspects-replace_aspect

• 🟩 execution_time [-667.324ns; -588.760ns] or [-9.182%; -8.101%]

scenario:iast_aspects-rsplit_aspect

• 🟩 execution_time [-176.985ns; -149.826ns] or [-9.598%; -8.125%]