Upgrade macOS CI to Apple Silicon

.github/workflows/Tests.yaml

@@ -858,17 +858,15 @@ ${{ matrix.build_type }}-pch-${{ matrix.use_pch || 'ON' }}"
   # Build all test executables and run unit tests on macOS
   unit_tests_macos:
     name: Unit tests on macOS
-    runs-on: macos-13
+    runs-on: macos-14
     env:
       # We install some low-level dependencies with Homebrew. They get picked up
       # by `spack external find`.
       SPECTRE_BREW_DEPS: >-  # Line breaks are spaces, no trailing newline
-        autoconf automake catch2 ccache cmake pkg-config boost
+        autoconf automake boost catch2 ccache cmake gsl hdf5 yaml-cpp
       # We install these packages with Spack and cache them. The full specs are
-      # listed in support/DevEnvironments/spack.yaml. This list is only needed
-      # to create the cache.
-      SPECTRE_SPACK_DEPS: >-
-        blaze charmpp gsl hdf5 libxsmm openblas yaml-cpp
+      # listed below. This list is only needed to create the cache.
+      SPECTRE_SPACK_DEPS: charmpp
       CCACHE_DIR: $HOME/ccache
       CCACHE_TEMPDIR: $HOME/ccache-tmp
       CCACHE_MAXSIZE: "2G"
@@ -877,6 +875,9 @@ ${{ matrix.build_type }}-pch-${{ matrix.use_pch || 'ON' }}"
       CCACHE_COMPILERCHECK: content
       SPACK_SKIP_MODULES: true
       SPACK_COLOR: always
+      # The number of cores to run on. This is given at:
+      # https://docs.github.com/en/actions/using-github-hosted-runners/about-github-hosted-runners/about-github-hosted-runners#supported-runners-and-hardware-resources
+      NUM_CORES: 3
     steps:
       - name: Record start time
         id: start
@@ -886,7 +887,7 @@ ${{ matrix.build_type }}-pch-${{ matrix.use_pch || 'ON' }}"
         uses: actions/checkout@v4
       - uses: actions/setup-python@v5
         with:
-          python-version: '3.10'
+          python-version: '3.12'
       - name: Install Homebrew dependencies
         run: |
           brew install $SPECTRE_BREW_DEPS
@@ -904,7 +905,7 @@ ${{ matrix.build_type }}-pch-${{ matrix.use_pch || 'ON' }}"
         run: |
           cd $HOME
           git clone -c feature.manyFiles=true --depth=1 \
-            --branch releases/v0.18 --single-branch \
+            --branch releases/v0.22 --single-branch \
             https://github.com/spack/spack.git
       - name: Configure Spack
         # - To avoid re-building packages that are already installed by Homebrew
@@ -914,7 +915,7 @@ ${{ matrix.build_type }}-pch-${{ matrix.use_pch || 'ON' }}"
           source $HOME/spack/share/spack/setup-env.sh
           spack debug report
           spack compiler find && spack compiler list
-          spack external find && spack external find perl python
+          spack external find
           spack config get packages
           spack mirror add dependencies file://$HOME/dependencies/spack
       # Install the remaining dependencies from source with Spack. We install
@@ -923,9 +924,9 @@ ${{ matrix.build_type }}-pch-${{ matrix.use_pch || 'ON' }}"
       - name: Install Spack dependencies
         run: |
           source $HOME/spack/share/spack/setup-env.sh
-          spack env create spectre support/DevEnvironments/spack.yaml
+          spack env create spectre
           spack env activate spectre
-          spack remove catch2 doxygen jemalloc boost
+          spack add charmpp@7.0.0 backend=multicore build-target=charm++
           spack concretize --reuse
           spack install --no-check-signature
           spack find -v
@@ -988,7 +989,7 @@ ${{ matrix.build_type }}-pch-${{ matrix.use_pch || 'ON' }}"
             -D OVERRIDE_ARCH=x86-64 \
             -D BUILD_SHARED_LIBS=ON \
             -D BUILD_PYTHON_BINDINGS=ON \
-            -D BOOTSTRAP_PY_DEPS=ON \
+            -D SPECTRE_FETCH_MISSING_DEPS=ON \
             -D MEMORY_ALLOCATOR=SYSTEM \
             -D CHARM_ROOT=$(spack location --install-dir charmpp) \
             -D CMAKE_BUILD_TYPE=Debug \
@@ -1005,10 +1006,8 @@ ${{ matrix.build_type }}-pch-${{ matrix.use_pch || 'ON' }}"
             $GITHUB_WORKSPACE
       - name: Build unit tests
         working-directory: build
-        # Build on 4 threads because GitHub's macOS VMs have 4 cores:
-        # https://docs.github.com/en/actions/using-github-hosted-runners/about-github-hosted-runners#supported-runners-and-hardware-resources
         run: |
-          make -j4 unit-tests
+          make -j${NUM_CORES} unit-tests
       - name: Build executables
         working-directory: build
         run: |
@@ -1036,7 +1035,7 @@ ${{ matrix.build_type }}-pch-${{ matrix.use_pch || 'ON' }}"
       - name: Run unit tests
         working-directory: build
         run: |
-          ctest -j4 --repeat after-timeout:3 --output-on-failure
+          ctest -j${NUM_CORES} --repeat after-timeout:3 --output-on-failure
       - name: Install
         working-directory: build
         run: |