github CI: use macOS 15 for x86

The macOS 13 one is being phased out.

Signed-off-by: Rosen Penev <[email protected]>

Author: neheb

.github/workflows/on_push_BasicWinLinMac.yml

@@ -86,8 +86,8 @@ jobs:
     strategy:
       matrix:
         runner:
-          - { os: macos-13,     arch: X64   }
-          - { os: macos-latest, arch: ARM64 }
+          - { os: macos-15-intel, arch: X64   }
+          - { os: macos-latest,   arch: ARM64 }
 
     steps:
       - uses: actions/checkout@v5
@@ -96,11 +96,6 @@ jobs:
         run: |
           brew install ninja inih googletest
 
-      - name: Install fmt on macOS 13
-        if: ${{ matrix.runner.os == 'macos-13' }}
-        run: |
-          brew install fmt
-
       - name: Build
         run: |
           cmake --preset base_mac -S . -B build

.github/workflows/release.yml

@@ -64,8 +64,8 @@ jobs:
     strategy:
       matrix:
         runner:
-          - { os: macos-13, arch: x64   }
-          - { os: macos-14, arch: arm64 }
+          - { os: macos-15-intel, arch: x64   }
+          - { os: macos-14,       arch: arm64 }
     steps:
       - uses: actions/checkout@v5
 
@@ -78,11 +78,6 @@ jobs:
           brew install doxygen
           brew install graphviz
 
-      - name: Install fmt on macOS 13
-        if: ${{ matrix.runner.os == 'macos-13' }}
-        run: |
-          brew install fmt
-
       - name: Build packaged release
         run: |
           mkdir build