CI: Include patch version in bundler cache

[marcotc]

What does this PR do?
I wasn't able to reproduce it since the cache has been updated, but I believe that errors is like:

Cache restored from key: bundle-Linux-X64-ruby-4.0.0-7c2bd67539b906e203ecae48542cf42de37302d288561cb379f3579582e983d1
Run bundle check
Source locally installed gems is ignoring #<Bundler::StubSpecification name=zstd-ruby version=2.0.5 platform=ruby> because it is missing extensions
Source locally installed gems is ignoring #<Bundler::StubSpecification name=strscan version=3.1.7 platform=ruby> because it is missing extensions
Source locally installed gems is ignoring #<Bundler::StubSpecification name=rbs version=3.10.2 platform=ruby> because it is missing extensions
Source locally installed gems is ignoring #<Bundler::StubSpecification name=prism version=1.7.0 platform=ruby> because it is missing extensions
Source locally installed gems is ignoring #<Bundler::StubSpecification name=msgpack version=1.8.0 platform=ruby> because it is missing extensions
Source locally installed gems is ignoring #<Bundler::StubSpecification name=json version=2.18.0 platform=ruby> because it is missing extensions
Source locally installed gems is ignoring #<Bundler::StubSpecification name=io-console version=0.8.2 platform=ruby> because it is missing extensions
Source locally installed gems is ignoring #<Bundler::StubSpecification name=google-protobuf version=3.25.8 platform=ruby> because it is missing extensions
Source locally installed gems is ignoring #<Bundler::StubSpecification name=ffi version=1.17.2 platform=ruby> because it is missing extensions
Source locally installed gems is ignoring #<Bundler::StubSpecification name=cgi version=0.5.1 platform=ruby> because it is missing extensions
Source locally installed gems is ignoring #<Bundler::StubSpecification name=byebug version=12.0.0 platform=ruby> because it is missing extensions
Source locally installed gems is ignoring #<Bundler::StubSpecification name=bigdecimal version=4.0.1 platform=ruby> because it is missing extensions
The following gems are missing
 * zstd-ruby (2.0.5)
 * google-protobuf (3.25.8)
 * byebug (12.0.0)
 * rbs (3.10.2)
 * ffi (1.17.2)
 * cgi (0.5.1)
 * msgpack (1.8.0)
 * strscan (3.1.7)
Install missing gems with `bundle install`

happen because the Ruby version (4.0.0 preview3) changed (to 4.0.0) without a change to the cache parameter.

This PR changes that to now use the full Ruby version string, which in includes patch level information, as well as OS and CPU architecture.
Examples:

• ruby 4.0.0 (2025-12-25 revision 553f1675f3) +PRISM [arm64-darwin24]
• ruby 4.0.0preview3 (2025-12-18 master cfa3e7cf75) +PRISM [arm64-darwin24]
• truffleruby 23.0.0-preview1, like ruby 3.1.3, GraalVM CE Native [aarch64-darwin]
• jruby 9.4.0.0 (3.1.0) 2022-11-23 95c0ec159f OpenJDK 64-Bit Server VM 25.472-b08 on 1.8.0_472-b08 [arm64-darwin]

Then cache key used by GH actions is not a direct file path, it's just a string, so I chose to simply keep the string as is.

Change log entry

No.

Additional Notes:

How to test the change?

[github-actions]

Thank you for updating Change log entry section 👏

^{Visited at: 2026-01-09 21:15:02 UTC}

[datadog-datadog-prod-us1]

✅ Tests

🎉 All green!

❄️ No new flaky tests detected
🧪 All tests passed

🎯 Code Coverage
• Patch Coverage: 100.00%
• Overall Coverage: 95.21% (-0.01%)

View detailed report

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