[Infra] Update Dockerfiles with dependabot

[martincostello]

Changes

Update dependabot configuration to keep the SDK versions in the Dockerfiles up-to-date on a weekly basis to match the .NET SDK in global.json.

Merge requirement checklist

• CONTRIBUTING guidelines followed (license requirements, nullable enabled, static analysis, etc.)
• Unit tests added/updated
• Appropriate CHANGELOG.md files updated for non-trivial changes
• Changes in public API reviewed (if applicable)

[Copilot]

Pull Request Overview

This PR updates the dependabot configuration to ensure that SDK versions in Dockerfiles remain in sync with the .NET SDK specified in global.json by scheduling weekly updates for Docker-based test directories.

• Added weekly dependabot schedules for three test directories using docker package-ecosystem.
• The updated configuration supports regular dependency updates for tests involving Cassandra, ConfluentKafka, and StackExchangeRedis.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 69.80%. Comparing base (71655ce) to head (6ae267f).
Report is 880 commits behind head on main.

✅ All tests successful. No failed tests found.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2838      +/-   ##
==========================================
- Coverage   73.91%   69.80%   -4.12%     
==========================================
  Files         267      394     +127     
  Lines        9615    15978    +6363     
==========================================
+ Hits         7107    11153    +4046     
- Misses       2508     4825    +2317     

Flag	Coverage Δ
unittests-Contrib.Shared.Tests	86.06% <ø> (?)
unittests-Exporter.Geneva	53.78% <ø> (?)
unittests-Exporter.InfluxDB	95.14% <ø> (?)
unittests-Exporter.Instana	74.86% <ø> (?)
unittests-Exporter.OneCollector	94.61% <ø> (?)
unittests-Exporter.Stackdriver	79.26% <ø> (?)
unittests-Extensions	90.65% <ø> (?)
unittests-Extensions.Enrichment	100.00% <ø> (?)
unittests-Instrumentation.AWS	84.01% <ø> (?)
unittests-Instrumentation.AspNet	76.79% <ø> (?)
unittests-Instrumentation.AspNetCore	70.32% <ø> (?)
unittests-Instrumentation.ConfluentKafka	14.10% <ø> (?)
unittests-Instrumentation.ElasticsearchClient	80.12% <ø> (?)
unittests-Instrumentation.EntityFrameworkCore	57.06% <ø> (?)
unittests-Instrumentation.EventCounters	76.36% <ø> (?)
unittests-Instrumentation.GrpcCore	91.42% <ø> (?)
unittests-Instrumentation.GrpcNetClient	79.61% <ø> (?)
unittests-Instrumentation.Hangfire	93.58% <ø> (?)
unittests-Instrumentation.Http	74.09% <ø> (?)
unittests-Instrumentation.Owin	88.62% <ø> (?)
unittests-Instrumentation.Process	100.00% <ø> (?)
unittests-Instrumentation.Quartz	78.76% <ø> (?)
unittests-Instrumentation.Runtime	100.00% <ø> (?)
unittests-Instrumentation.ServiceFabricRemoting	34.54% <ø> (?)
unittests-Instrumentation.SqlClient	87.82% <ø> (?)
unittests-Instrumentation.StackExchangeRedis	70.92% <ø> (?)
unittests-Instrumentation.Wcf	78.75% <ø> (?)
unittests-PersistentStorage	65.88% <ø> (?)
unittests-Resources.AWS	75.00% <ø> (?)
unittests-Resources.Azure	84.56% <ø> (?)
unittests-Resources.Container	67.34% <ø> (?)
unittests-Resources.Gcp	71.42% <ø> (?)
unittests-Resources.Host	73.91% <ø> (?)
unittests-Resources.OperatingSystem	76.98% <ø> (?)
unittests-Resources.Process	100.00% <ø> (?)
unittests-Resources.ProcessRuntime	78.26% <ø> (?)
unittests-Sampler.AWS	88.25% <ø> (?)

Flags with carried forward coverage won't be shown. Click here to find out more.

see 395 files with indirect coverage changes

🚀 New features to boost your workflow:

• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

[TimothyMothra]

just curious, would it make sense to scan the entire "test/*" directory?

[martincostello]

I genuinely don't know if it recurses or not.

[TimothyMothra]

Looks like it can :)
I think we should give this a try.

https://docs.github.com/en/code-security/dependabot/dependabot-version-updates/controlling-dependencies-updated#:~:text=To%20specify%20manifests%20in%20the%20current%20directory%20and%20recursive%20subdirectories

# Specify all directories from the current layer and below recursively,
# using globstar, for locations of manifest files

version: 2
updates:
  - package-ecosystem: "composer"
    directories:
      - "**/*"
    schedule:
      interval: "weekly"