Change "Try GitLab for Free" to "Try GitLab Free" across website

This MR updates the CTA needs from "Try GitLab for Free" to "Try GitLab Free" on all pages that use this partial "includes/blog/try".

Here's a screenshot of the module getting updated with this MR:

This partial is included on many pages and effectly changes the CTA on all pages that use the following layouts

• /sites/marketing/source/layouts/feature.haml (all pages that use feature layout)
• /sites/marketing/source/layouts/post.haml (all blog posts)
• /source/layouts/release.haml (all release posts)

And it changes the following pages

• https://about.gitlab.com/releases/gitlab-com/
• https://about.gitlab.com/solutions/kubernetes/
• https://about.gitlab.com/stages-devops-lifecycle/pages/

Related #8742 (closed)

Adjustment Category

Which adjustment is this MR related to:

• Content/Messaging
• Brand/Design UX - Mobile
• Brand/Design UX - Desktop
• Dev/Webpage Element (ie CTA box)
• Backend/Analytics
• Other (Specify below)

Items on page to be udpated

DRI see issue and issue design tab for more information if needed

• Update CTA for consistency to "Try GitLab free" (comment 2)
• Update header copy (comment 5)
• Review page copy and update for clarity and consistency

Roles and Responsibilies

Name	Role
@rreich	Project Lead
@erica	Content/Messaging Team Lead
@vsilverthorne	MR DRI

Production:

Project Lead

• Fill out
• Confirm it is related to the issue
• Assign to relevant Team Lead

Team Lead

• Assign to DRI

DRI

• Make adjustments
• Assign to Team Lead for review
• All threads resolved assign to Web Dev Lead

Wed Dev Lead

• Review and merge