CI: reduce the test matrix

For the sake or reducing test flakes

Signed-off-by: Akihiro Suda <[email protected]>

.github/workflows/lima.yaml

@@ -13,17 +13,7 @@ permissions:
 jobs:
   integration:
     name: Integration tests
-    strategy:
-      fail-fast: false
-      matrix:
-        # macos-13-large is used as macos-13 seems too flaky.
-        # macos-14 (ARM) and later cannot be used for the most part of the job
-        # due to the lack of the support for nested virt.
-        platform:
-          - macos-13-large
-          - macos-14-large
-          - macos-15-large
-    runs-on: ${{ matrix.platform }}
+    runs-on: macos-15-large
     # Typically takes 8 minutes. If a step get stuck for many mintues it is
     # unlikely to succeed.
     timeout-minutes: 20
@@ -53,8 +43,7 @@ jobs:
           make ARCH=arm64
           sudo make PREFIX=/opt/socket_vmnet.arm64 install.bin install.doc
           if file /opt/socket_vmnet.arm64/bin/* | grep -q x86_64 ; then false ; fi
-      - name: Update brew (macos-15-large)
-        if: matrix.platform == 'macos-15-large'
+      - name: Update brew
         # Without this we get lima 0.23.2 instead of latest release.
         run: brew update
       - name: Install Lima