Update main.yml

Author: asottile-sentry

.github/workflows/main.yml

@@ -2,17 +2,12 @@ on:
   push:
 jobs:
   main:
-    runs-on: macos-14
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        instance: [0, 1, 2, 3]
     steps:
-    - run: |
-        set -x
-        brew install docker colima
-        colima start || (cat /Users/runner/.colima/_lima/colima/ha.stderr.log && exit 1)
-    - run: docker run --rm ubuntu:jammy bash -c 'echo hi'
-  main2:
-    runs-on: macos-13
-    steps:
-    - run: |
-        brew install docker colima
-        colima start
-    - run: docker run --rm ubuntu:jammy bash -c 'echo hi'
+    - run: ip addr
+      if: matrix.instance == 0
+    - run: echo worker
+      if: matrix.instance != 0