Schedule builder only to AMD nodes

.woodpecker/build.yaml

@@ -3,6 +3,11 @@ when:
   event:
     - push
 
+matrix:
+  include:
+    - NAME: AMD
+      ARCH: amd64
+
 steps:
   build:
     image: zot.badhouseplants.net/badhouseplants/badhouseplants-builder:latest
@@ -27,3 +32,5 @@ steps:
             cpu: 1000m
         securityContext:
           privileged: true
+        nodeSelector:
+          kubernetes.io/arch: "${ARCH}"