Update Devops Lifecycle Graphic

Why is this change being made?

This MR updates the website per gitlab-org/gitlab-design#2106 (closed) and changes the style of the DevOps lifecycle graphic

Review App Pages:

• https://sam-update-devops-loop.about.gitlab-review.app/handbook/product/categories/
• https://sam-update-devops-loop.about.gitlab-review.app/direction/
• https://sam-update-devops-loop.about.gitlab-review.app/direction/dev/
• https://sam-update-devops-loop.about.gitlab-review.app/direction/security/
• https://sam-update-devops-loop.about.gitlab-review.app/direction/ops/
• https://sam-update-devops-loop.about.gitlab-review.app/direction/create/
• https://sam-update-devops-loop.about.gitlab-review.app/direction/delivery/
• https://sam-update-devops-loop.about.gitlab-review.app/direction/govern/
• https://sam-update-devops-loop.about.gitlab-review.app/direction/manage/
• https://sam-update-devops-loop.about.gitlab-review.app/direction/monitor/
• https://sam-update-devops-loop.about.gitlab-review.app/direction/plan/
• https://sam-update-devops-loop.about.gitlab-review.app/direction/secure/
• https://sam-update-devops-loop.about.gitlab-review.app/direction/verify/
• https://sam-update-devops-loop.about.gitlab-review.app/press/press-kit/

New Images:

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Dark
Partial

Author Checklist

• Provided a concise title for this Merge Request (MR)
• Added a description to this MR explaining the reasons for the proposed change, per say why, not just what
  • Copy/paste the Slack conversation to document it for later, or upload screenshots. Verify that no confidential data is added.
• Assign reviewers for this MR to the correct Directly Responsible Individual/s (DRI)
  • If the DRI for the page/s being updated isn’t immediately clear, then assign it to one of the people listed in the Maintained by section on the page being edited
  • If your manager does not have merge rights, please ask someone to merge it AFTER it has been approved by your manager in #mr-buddies
• If the changes affect team members, or warrant an announcement in another way, please consider posting an update in #whats-happening-at-gitlab linking to this MR
  • If this is a change that directly impacts the majority of global team members, it should be a candidate for #company-fyi. Please work with internal communications and check the handbook for examples.

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