Use dollar sign prefix for variables for GHA

[maximiliankolb]

rg "\{\{" .github

• Refs 242dde2 (PR 3579 on GitHub)
• Refs 313e77e (PR 3584 on GitHub)

What changes are you introducing?

add missing dollar signs

Why are you introducing these changes? (Explanation, links to references, issues, etc.)

to make GH previews work again 🤞

Anything else to add? (Considerations, potential downsides, alternative solutions you have explored, etc.)

Checklists

• I am okay with my commits getting squashed when you merge this PR.
• I am familiar with the contributing guidelines.

no cherry-picks

[ekohl]

In #3587 I tried this too, but quoted to be sure it's a single argument and also tried the download of multiple at the same time. Not sure what you prefer.

[maximiliankolb]

In #3587 I tried this too, but quoted to be sure it's a single argument and also tried the download of multiple at the same time. Not sure what you prefer.

Quoting probably makes sense -> closing this PR.