Switch macos-13 CI jobs to macos-15-intel (#4442)

macOS 13 runner images will be retired by 2025-12-04:
https://github.blog/changelog/2025-09-19-github-actions-macos-13-runner-image-is-closing-down/.

By submitting this pull request, I confirm that my contribution is made
under the terms of the Apache 2.0 and MIT licenses.

Author: tautschnig

.github/workflows/cbmc-latest.yml

@@ -22,7 +22,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        os: [macos-13, ubuntu-22.04, ubuntu-24.04]
+        os: [macos-15-intel, ubuntu-22.04, ubuntu-24.04]
     steps:
       - name: Checkout Kani under "kani"
         uses: actions/checkout@v5

.github/workflows/kani.yml

@@ -20,7 +20,7 @@ jobs:
       contents: read
     strategy:
       matrix:
-        os: [macos-13, ubuntu-22.04, ubuntu-24.04, macos-14, ubuntu-24.04-arm]
+        os: [macos-15-intel, ubuntu-22.04, ubuntu-24.04, macos-14, ubuntu-24.04-arm]
     steps:
       - name: Checkout Kani
         uses: actions/checkout@v5

.github/workflows/release.yml

@@ -24,7 +24,7 @@ env:
 jobs:
   build_bundle_macos_x86_64:
     name: BuildBundle-MacOs-x86_64
-    runs-on: macos-13
+    runs-on: macos-15-intel
     outputs:
       version: ${{ steps.bundle.outputs.version }}
       bundle: ${{ steps.bundle.outputs.bundle }}
@@ -37,7 +37,7 @@ jobs:
       - name: Setup Kani Dependencies
         uses: ./.github/actions/setup
         with:
-          os: macos-13
+          os: macos-15-intel
 
       - name: Build bundle
         id: bundle
@@ -119,9 +119,9 @@ jobs:
     needs: [build_bundle_macos_x86_64, build_bundle_macos_aarch64, build_bundle_linux_x86_64, build_bundle_linux_aarch64]
     strategy:
       matrix:
-        os: [macos-13, macos-14, ubuntu-22.04, ubuntu-24.04, ubuntu-24.04-arm]
+        os: [macos-15-intel, macos-14, ubuntu-22.04, ubuntu-24.04, ubuntu-24.04-arm]
         include:
-        - os: macos-13
+        - os: macos-15-intel
           rust_target: x86_64-apple-darwin
           prev_job: ${{ needs.build_bundle_macos_x86_64.outputs }}
         - os: macos-14
@@ -225,11 +225,11 @@ jobs:
     needs: [build_bundle_macos_x86_64, build_bundle_macos_aarch64, build_bundle_linux_x86_64, build_bundle_linux_aarch64]
     strategy:
       matrix:
-        os: [macos-13, macos-14, ubuntu-22.04, ubuntu-24.04, ubuntu-24.04-arm]
+        os: [macos-15-intel, macos-14, ubuntu-22.04, ubuntu-24.04, ubuntu-24.04-arm]
         include:
           # Stores the output of the previous job conditional to the OS
           - prev_job: ${{ needs.build_bundle_linux_x86_64.outputs }}
-          - os: macos-13
+          - os: macos-15-intel
             prev_job: ${{ needs.build_bundle_macos_x86_64.outputs }}
           - os: macos-14
             prev_job: ${{ needs.build_bundle_macos_aarch64.outputs }}

.github/workflows/slow-tests.yml

@@ -21,7 +21,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        os: [macos-13, ubuntu-22.04, ubuntu-24.04]
+        os: [macos-15-intel, ubuntu-22.04, ubuntu-24.04]
     steps:
       - name: Checkout Kani
         uses: actions/checkout@v5

scripts/setup/macos-15

@@ -0,0 +1 @@
+macos

scripts/setup/macos-15-intel

@@ -0,0 +1 @@
+macos