Remove llvm 18 ci osx15 cling job

Author: mcbarton

.github/workflows/ci.yml

@@ -297,6 +297,7 @@ jobs:
             cling_on=$(echo "${{ matrix.cling }}" | tr '[:lower:]' '[:upper:]')
             if [[ "${cling_on}" == "ON" ]]; then  
                 brew install llvm@15
+                brew remove llvm@18
                 echo "CC=$(brew --prefix llvm@15)/bin/clang" >> $GITHUB_ENV
                 echo "CXX=$(brew --prefix llvm@15)/bin/clang++" >> $GITHUB_ENV
             else
@@ -777,6 +778,7 @@ jobs:
             cling_on=$(echo "${{ matrix.cling }}" | tr '[:lower:]' '[:upper:]')
             if [[ "${cling_on}" == "ON" ]]; then  
                 brew install llvm@15
+                brew remove llvm@18
                 echo "CC=$(brew --prefix llvm@15)/bin/clang" >> $GITHUB_ENV
                 echo "CXX=$(brew --prefix llvm@15)/bin/clang++" >> $GITHUB_ENV
             else