meta: add more architectures

.forgejo/workflows/build.yaml

@@ -2,14 +2,20 @@ on:
   push:
 
 jobs:
-  build-x86_64: &build
+  build:
-    container: registry.git.ptrc.gay/ptrcnull/ptrcports-builder/x86_64:latest
+    strategy:
+      matrix:
+        arch:
+          - x86_64
+          - aarch64
+          - armv7
+    container: registry.git.ptrc.gay/ptrcnull/ptrcports-builder/${{ matrix.arch }}:latest
     steps:
       - uses: https://code.forgejo.org/actions/checkout@v4
       - uses: https://code.forgejo.org/actions/cache@v4
         with:
           path: ~/repodest
-          key: ${{ runner.os }}-ptrcports
+          key: ${{ matrix.arch }}-ptrcports
 
       - name: Set up secrets
         run: |