Update azure-functions-lab.md

[cmatskas]

Updated the Free Azure Subscription link to point to a page more relevant to the user

(You can replace all of this text with your description.)

Before creating your pull request, please check your content against these quality criteria:

• Did you consider search engine optimization (SEO) when you chose the title in the metadata section and the H1 heading (i.e. the displayed title that starts with a single #)?
• For new articles, did you add it to the table of contents?
• Did you update the "ms.date" metadata for new or significantly updated articles?
• Are technical terms and concepts introduced and explained, and are acronyms spelled out on first mention?
• Should this page be linked to from other pages or Microsoft web sites?

For more information about creating content for docs.microsoft.com, see the contributor guide at https://docs.microsoft.com/contribute/.

[PRMerger13]

@cmatskas : Thanks for your contribution! The author(s) have been notified to review your proposed change.

[cmatskas]

#sign-off

[PRMerger19]

@cmatskas: I'm sorry - only the author of this article, @sayedihashimi, can sign off on your changes. But we do have an exception process - if you are on the Microsoft content or product team for this product area, you can ask the PR review team to review and merge it by sending mail to the techdocprs alias.

[Jak-MS]

@cmatskas - in the public repo, only the article author can sign off. thanks.

[ktoliver]

@sayedihashimi - Could you review the proposed changes? Thanks.

[sayedihashimi]

Looks good

[sayedihashimi]

#sign-off