New versions of ruby_buildpack do not include pinned Ruby version

[Kumbirai Tanekha]

Summary

The conjur-service-broker on the main branch is failing to deploy on Tanzu clusters (TAS foundatio) that have new releases of the ruby_buildpack (>= v1.8.38), which do not include the pinned Ruby version (2.5.8) for the service broker.

Steps to Reproduce

Steps to reproduce the behavior:

1. Update the ruby_buildpack on Tanzu cluster to v1.8.38
2. Deploy the conjur-service-broker on the main branch
3. See the following error

   2021-07-30T22:10:06.46+0100 [STG/0] OUT -----> Ruby Buildpack version 1.8.42
   2021-07-30T22:10:06.46+0100 [STG/0] OUT -----> Supplying Ruby
   2021-07-30T22:10:06.51+0100 [STG/0] OUT -----> Installing bundler 1.17.3
   2021-07-30T22:10:06.51+0100 [STG/0] OUT        Copy [/tmp/buildpacks/886d17158aa90191a4c8181a05fd296b/dependencies/1b585b3a526373724c47492bbb271365/bundler-1.17.3-any-stack-b7502506.tgz]
   2021-07-30T22:10:06.79+0100 [STG/0] OUT        **ERROR** Unable to determine ruby: Unable to determine ruby version: Running ruby: No Matching versions, ruby = 2.5.8 not found in this buildpack

Expected Results

Service broker should deploy successfully. It should use a buildpack that provides it with the pinned Ruby version (2.5.8).

Reproducible

• Always
• Sometimes
• Non-Reproducible