Allow symbols in breadcrumb meta data

[tomlongridge]

Goal

Complex types are currently disallowed as values of metadata on breadcrumbs, however Symbols can be allowed as they will serialise to string without issue.

Changeset

Changed

• validator.rb - add Symbol type to list of allowed types

Tests

• Added symbol as part of existing validator_spec.rb test

Review

For the submitter, initial self-review:

• Commented on code changes inline explain the reasoning behind the approach
• Reviewed the test cases added for completeness and possible points for discussion
• A changelog entry was added for the goal of this pull request
• Check the scope of the changeset - is everything in the diff required for the pull request?
• This pull request is ready for:
  • Initial review of the intended approach, not yet feature complete
  • Structural review of the classes, functions, and properties modified
  • Final review

For the pull request reviewer(s), this changeset has been reviewed for:

• Consistency across platforms for structures or concepts added or modified
• Consistency between the changeset and the goal stated above
• Internal consistency with the rest of the library - is there any overlap between existing interfaces and any which have been added?
• Usage friction - is the proposed change in usage cumbersome or complicated?
• Performance and complexity - are there any cases of unexpected O(n^3) when iterating, recursing, flat mapping, etc?
• Concurrency concerns - if components are accessed asynchronously, what issues will arise
• Thoroughness of added tests and any missing edge cases
• Idiomatic use of the language

[tomlongridge]

Reimplemented the change from #561 with tests and changelog.

[directionless]

This would fix #539

[tobyhs]

lgtm

[directionless]

Hi @tomlongridge! I wanted to thank you for picking up my patch and adding in tests and a changelog. But, I did want to mention that it felt a bit off in etiquette. By closing my PR and pulling the diff here, I don't get credit for the work. It's a small thing, but it's one of the things that keeps me involved with open source.

I find that a better process is to ask the PR author to do those things (or ask for write permissions on their branch and do it for them with their permission).

There are additional technical solutions, like cherry-picking and co-authored PRs.

[tomlongridge]

@directionless - my apologies, you're right. I've now cherry-picked your commit into this PR.

[directionless]

@tomlongridge Thank you! I appreciate it