ci: Add support for GitHub's merge queue (#338)

Author: alessfg

.github/workflows/alpine-mainline.yml

@@ -2,6 +2,7 @@
 name: Alpine Mainline
 on:
   pull_request:
+  merge_group:
   schedule:
     - cron: "0 0 * * 1"
   workflow_dispatch:

.github/workflows/alpine-stable.yml

@@ -2,6 +2,7 @@
 name: Alpine Stable
 on:
   pull_request:
+  merge_group:
   schedule:
     - cron: "0 0 * * 1"
   workflow_dispatch:

.github/workflows/debian-mainline.yml

@@ -2,6 +2,7 @@
 name: Debian Mainline
 on:
   pull_request:
+  merge_group:
   schedule:
     - cron: "0 0 * * 1"
   workflow_dispatch:

.github/workflows/debian-stable.yml

@@ -2,6 +2,7 @@
 name: Debian Stable
 on:
   pull_request:
+  merge_group:
   schedule:
     - cron: "0 0 * * 1"
   workflow_dispatch: