Switch to GHCR containers (#297)

Author: davidmhewitt

.github/workflows/gettext.yml

@@ -2,13 +2,13 @@ name: Gettext Updates
 
 on:
   push:
-    branches: master
+    branches: [master]
 
 jobs:
   build:
     runs-on: ubuntu-22.04
     container:
-      image: elementary/docker:next-unstable
+      image: ghcr.io/elementary/docker:next-unstable
 
     steps:
     - name: Install git

.github/workflows/main.yml

@@ -1,13 +1,22 @@
 name: CI
 
-on: [push, pull_request]
+on:
+  pull_request:
+    types:
+      - opened
+      - reopened
+      - synchronize
 
 jobs:
   build:
     runs-on: ubuntu-latest
 
+    strategy:
+      fail-fast: false
+      matrix:
+        version: [stable, unstable, development-target]
     container:
-      image: elementary/docker:unstable
+      image: ghcr.io/elementary/docker:${{ matrix.version }}
 
     steps:
       - uses: actions/checkout@v3

.github/workflows/release.yml

@@ -2,8 +2,8 @@ name: Release
 
 on:
   pull_request:
-    branches: master
-    types: closed
+    branches: [master]
+    types: [closed]
 jobs:
   release:
     runs-on: ubuntu-latest