docs: add 'Contribute to PipeCD Blogs' guide

[shivansh-gohem]

Hi @eeshaanSA and @khanhtc1202,

Following up on my previous PR, this tackles the 'Contribute to PipeCD Blogs' section of Epic #6124, as requested.

This PR adds the new guide, which includes:

• The required blog post frontmatter (date, author, categories, etc.).
• Guidelines for submitting new blog content.

This completes the second major section of the overall Contributing Epic. Thanks for the review!

[eeshaanSA]

@shivansh-gohem, why dont you try contributing to the blog before you close this PR? This way, you will know exactly what to put in into this PR 👀

I dont know how much you are familiar with PipeCD or CI/CD in general, but if you are not, let's get you started.

Have you joined the PiepCD slack channel yet?

[shivansh-gohem]

Hi @eeshaanSA,

Thanks again for the patience and detailed guidance. I've completed all the remaining tasks:

Code Status: I've applied the final changes (including the simplified description and the linkTitle fix) and pushed the update.

Slack: I've successfully joined the #pipecd Slack channel.

I must admit, while I'm enthusiastic about contributing, my knowledge of CI/CD and PipeCD's internals is still small. I understand the documentation process well now, but I could really use some help on the technical side of the project.

I'm ready to tackle the blog post next, but I'm looking for guidance on a specific topic that would be valuable to the community.

Could you guide me on a topic or suggest a focus area for my first blog post that would best showcase PipeCD?

Thanks for getting me started!

[eeshaanSA]

@shivansh-gohem, I cant see you on the slack channel yet. 👀

And I can see from your other PRs that you were successful in setting up a local build of PipeCD and even deployed a sample k8s application.

I think it would be great to have a blog/guide on how to setup PipeCD locally. What do you think?