Update macOS CI to use macos-15-intel

Author: yangao07

.github/workflows/macos-CI.yml

@@ -10,7 +10,7 @@ jobs:
   build-macos:
     strategy:
       matrix:
-        os: [macos-latest, macos-13] # test on arm64 and x64
+        os: [macos-latest, macos-15-intel] # test on arm64 and x64
     runs-on: ${{ matrix.os }}
 
     steps:
@@ -29,4 +29,4 @@ jobs:
          ./bin/abpoa ./test_data/seq.fa -a1
          ./bin/abpoa ./test_data/seq.fa -r5 -a1
          ./bin/abpoa ./test_data/heter.fq -d2 -Q
-         ./bin/abpoa ./test_data/heter.fq -d2 -r2 -Q -a1
+         ./bin/abpoa ./test_data/heter.fq -d2 -r2 -Q -a1