[CI] Move away from deprecated macos-13 runner

Author: mxmlnkn

.github/workflows/test-python.yml

@@ -27,7 +27,7 @@ jobs:
         python-version: ['3.9', '3.13', '3.14']
         # 2024-04-27: macos-latest, which points to macos-14-arm64, does not work anymore because of error 134 close
         #             towards the end when testing with parallelization=8. Could be a problem with compiling for ARM.
-        os: [macos-13, macos-14, macos-15, ubuntu-latest, ubuntu-24.04-arm, windows-latest]
+        os: [macos-14, macos-15, macos-15-intel, ubuntu-latest, ubuntu-24.04-arm, windows-latest]
 
     steps:
     - uses: actions/checkout@v4

.github/workflows/wheels-rapidgzip.yml

@@ -47,7 +47,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        os: [macos-13, macos-14, macos-15, ubuntu-24.04-arm, ubuntu-latest, windows-latest]
+        os: [macos-14, macos-15, macos-15-intel, ubuntu-24.04-arm, ubuntu-latest, windows-latest]
         archs: [auto64]
         manylinux-image: [manylinux_2_28]
         # Build with both x86-64 (macos-13) and ARM64 (macos-14) runners.