Update gems for ci

[jaggederest]

What does this pull request do?

Update gems for ci to resolve various issues:

• JSON gem is segfaulting when parsing an empty string on ruby >=3.0.4 issue in json repo
• sneakers on latest issued version (2.12.0) is pinned to an old version of rake, which causes build issues with http-parser gem's c extensions. Repin it to the HEAD of the current repository with a reference to prevent unexpected failures.
• Also make bundling sneakers gem optional since the HEAD version above depends on ruby >= 2.5, and make specs conditional on that gem spec being loaded in the process.
• rake pinned to >=13.0 to address above build issue, ensure that it does not reoccur spontaneously when bundling e.g. old versions of rails that may depend on it.

Why is it important?

This should fix CI to make moving development forward possible.

Checklist

• I have signed the Contributor License Agreement.
• My code follows the style guidelines of this project (See .rubocop.yml)
• I have rebased my changes on top of the latest main branch

• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

• I have made corresponding changes to the documentation
• I have updated CHANGELOG.asciidoc
• I have updated supported-technologies.asciidoc
• Added an API method or config option? Document in which version this will be introduced

Related issues

[ghost]

💚 Build Succeeded

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Build stats

• Start Time: 2022-05-12T10:36:16.884+0000

• Duration: 35 min 0 sec

Test stats 🧪

Test	Results
Failed	0
Passed	44189
Skipped	80
Total	44269

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[jaggederest]

NB recommend reviewing this with 'hide whitespace' enabled: https://github.com/elastic/apm-agent-ruby/pull/1259/files?diff=split&w=1 otherwise the spec changes are difficult to review

[ghost]

🌐 Coverage report

Name	Metrics % (covered/total)	Diff
Packages	100.0% (1/1)	💚
Files	99.2% (124/125)	❕
Classes	99.2% (124/125)	❕
Lines	59.594% (2497/4190)	❕
Conditionals	100.0% (0/0)	💚