chore: add sccache to testrunner docker image

[taegyunkim]

Tested locally

1. modify docker-compose.yml

     testrunner:
        build:
          context: ./docker
          dockerfile: Dockerfile

2. run tests using riot run

Checklist

• [x] 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

• [x] 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[bot]]

CODEOWNERS have been resolved as:

docker/Dockerfile                                                       @DataDog/apm-core-python

[datadog-dd-trace-py-rkomorn[bot]]

Datadog Report

Branch report: taegyunkim/ddtest-docker-sccache Commit report: cd9e650 Test service: dd-trace-py

:white_check_mark: 0 Failed, 121249 Passed, 55567 Skipped, 4h 13m 10.7s Total duration (4h 50m 12.21s time saved)

[pr-commenter[bot]]

Benchmarks

Benchmark execution time: 2024-08-14 18:05:19

Comparing candidate commit cd9e650279b9a3d56df53361ce072a6058809fb8 in PR branch taegyunkim/ddtest-docker-sccache with baseline commit 96ce8a2812c5e3cfd7f4058ed2a485d8a84be11a in branch main.

Found 0 performance improvements and 0 performance regressions! Performance is the same for 353 metrics, 47 unstable metrics.