Adds StepZen to Services block

[stepr-hw]

Pre-submission checklist:

Please check each of these after submitting your pull request:

• [ ] Are you only including a repo_url if your project is 100% open source? If so, you need to pick the single best GitHub repository for your project, not a GitHub organization.
• [ ] Is your project closed source or, if it is open source, does your project have at least 250 GitHub stars?
• [ ] Have you picked the single best (existing) category for your project?
• [ ] Does it follow the other guidelines from the new entries section?
• [ ] Have you included a URL for your SVG or added it to hosted_logos and referenced it there?
• [ ] Does your logo clearly state the name of the project/product and follow the other logo guidelines?
• [ ] Does your project/product name match the text on the logo?
• [ ] Have you verified that the Crunchbase data for your organization is correct (including headquarters and LinkedIn)?
• [ ] ~10 minutes after opening the pull request, the CNCF-Bot will post the URL for your staging server. Have you confirmed that it looks good to you and then added a comment to the PR saying "LGTM"?

[CNCF-Bot]

Build failed because of:
item StepZen has an invalid repo https://github.com/stepzen-dev

[netlify[bot]]

❌ Deploy Preview for graphql-landscape failed.

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