ci: Only build Fx for PRs (#1890)

* ci: Only build Fx for PRs

And not when landing a PR in `main`.

Signed-off-by: Lars Eggert <lars@eggert.org>

* Add `workflow_dispatch`

Signed-off-by: Lars Eggert <lars@eggert.org>

---------

Signed-off-by: Lars Eggert <lars@eggert.org>

.github/workflows/firefox.yml

@@ -1,12 +1,9 @@
 name: Firefox
 on:
- push:
- branches: ["main"]
- paths-ignore: ["*.md", "*.png", "*.svg", "LICENSE-*"]
+ workflow_dispatch:
  pull_request:
  branches: ["main"]
  paths-ignore: ["*.md", "*.png", "*.svg", "LICENSE-*"]
- merge_group:
 
 concurrency:
  group: ${{ github.workflow }}-${{ github.ref_name }}