fix: use deep merge strategy for context and options in Plugin

[xllily]

Initially, I attempted to modify the "source" order in Object.assign, but upon further consideration, I realized that utilizing a deep merge strategy would be a safer approach.

[webpro]

Thanks @xllily! Could you please give an example of what this change will fix? And given that Lodash is already a dependency, why did you choose to add a custom deepMerge?

[xllily]

Thanks @xllily! Could you please give an example of what this change will fix? And given that Lodash is already a dependency, why did you choose to add a custom deepMerge?

Thank you @webpro for your feedback! I apologize for not providing an example initially.

Regarding the issue with the log output in the terminal after a successful release, let me explain further. The example .release-it.json configuration you provided includes a custom registry URL (https://{{my-custom-host}}/) for npm publishing. However, despite this configuration, the log in the terminal still displays the default npm registry URL (https://www.npmjs.com/package/{{my-package}}).

I understand that this behavior is unexpected, and it aligns with the issue mentioned in #997. The purpose of my pull request was to address this issue and ensure that the log output in the terminal reflects the custom registry URL specified in the configuration.

As for the inclusion of the custom deepMerge implementation, I have realized that it may not be necessary in this case. I understand that Lodash is already a dependency, and its merge function can effectively handle the merging requirements. I have updated the pull request accordingly to reflect this realization.

Once again, thank you for your valuable feedback and guidance. I appreciate your assistance in improving the pull request, and I apologize for any confusion caused by my initial approach. Please let me know if there are any further concerns or suggestions.

[webpro]

Thanks @xllily! This is great, happy to merge.

[webpro]

🚀 This pull request is included in v15.10.4. See Release 15.10.4 for release notes.