MacOSX LLVM woes

Author: rocky

.github/workflows/osx.yml

@@ -21,9 +21,9 @@ jobs:
         python-version: ${{ matrix.python-version }}
     - name: Install dependencies
       run: |
-        brew install llvm@9
+        brew install llvm@11
         python -m pip install --upgrade pip
-        LLVM_CONFIG=/usr/local/Cellar/llvm@9/9.0.1_2/bin/llvm-config pip install llvmlite
+        LLVM_CONFIG=/usr/local/Cellar/llvm@11/11.1.0/bin/llvm-config pip install llvmlite
     - name: Install Mathics
       run: |
         make develop