CI: Update flatpak-builder and flat-manager actions

actions/cache versions other than v4, v3, v4.2.0, and v3.4.0 were
deprecated and gradually sunset through February.

@actions/cache versions other than v4.0.0+ were deprecated and gradually
sunset through February.

See:
 * https://github.com/actions/cache/discussions/1510
 * https://github.com/actions/toolkit/discussions/1890

flathub-infra/flatpak-github-actions/flatpak-builder set its
@actions/cache dependency version to "^3.2.3" and was last updated on
July 29, 2024. As a result, its yarn.lock file specifies version
"3.2.4", which is no longer supported and does not work.

Update flathub-infra/flatpak-github-actions actions now that they have
updated their @actions/cache dependency.

.github/workflows/build-project.yaml

@@ -292,7 +292,7 @@ jobs:
           path: build-aux/com.obsproject.Studio.json
 
       - name: Build Flatpak Manifest 🧾
-        uses: flathub-infra/flatpak-github-actions/flatpak-builder@e5fa5a8fe51d76f770ad9d240e4ad5898b1c6a53
+        uses: flathub-infra/flatpak-github-actions/flatpak-builder@42d281a5cf2ad1d0882a66af700a62cdad7686c6
         with:
           build-bundle: ${{ fromJSON(needs.check-event.outputs.package) }}
           bundle: obs-studio-flatpak-${{ needs.check-event.outputs.commitHash }}.flatpak

.github/workflows/publish.yaml

@@ -107,7 +107,7 @@ jobs:
           path: build-aux/com.obsproject.Studio.json
 
       - name: Build Flatpak Manifest
-        uses: flathub-infra/flatpak-github-actions/flatpak-builder@e5fa5a8fe51d76f770ad9d240e4ad5898b1c6a53
+        uses: flathub-infra/flatpak-github-actions/flatpak-builder@42d281a5cf2ad1d0882a66af700a62cdad7686c6
         with:
           build-bundle: false
           manifest-path: ${{ github.workspace }}/build-aux/com.obsproject.Studio.json
@@ -142,7 +142,7 @@ jobs:
           path: repo
 
       - name: Publish to Flathub Beta
-        uses: flathub-infra/flatpak-github-actions/flat-manager@e5fa5a8fe51d76f770ad9d240e4ad5898b1c6a53
+        uses: flathub-infra/flatpak-github-actions/flat-manager@42d281a5cf2ad1d0882a66af700a62cdad7686c6
         if: ${{ matrix.branch == 'beta' }}
         with:
           flat-manager-url: https://hub.flathub.org/
@@ -151,7 +151,7 @@ jobs:
           build-log-url: ${{ github.server_url }}/${{ github.repository }}/actions/runs/${{ github.run_id }}
 
       - name: Publish to Flathub
-        uses: flathub-infra/flatpak-github-actions/flat-manager@e5fa5a8fe51d76f770ad9d240e4ad5898b1c6a53
+        uses: flathub-infra/flatpak-github-actions/flat-manager@42d281a5cf2ad1d0882a66af700a62cdad7686c6
         if: ${{ matrix.branch == 'stable' }}
         with:
           flat-manager-url: https://hub.flathub.org/