matrix workflow fix mac pdffit2 install (#201)

* matrix workflow fix mac pdffit2 install

* fix pcmt

Author: Tieqiong

.github/workflows/matrix.yml

@@ -19,7 +19,7 @@ jobs:
             python-version: ['3.10', '3.11', '3.12']
             os: ["macos-latest", "ubuntu-latest", "windows-latest"]
     steps:
-      - name: check out test_workflow
+      - name: check out diffpy.pdfgui
         uses: actions/checkout@v4
 
       - name: Initialize miniconda
@@ -36,13 +36,20 @@ jobs:
           conda config --set always_yes yes
           --set changeps1 no
 
-      - name: Install test_workflow and requirements
+      - name: Install diffpy.pdfgui and requirements
         run: |
           conda install --file requirements/run.txt
           conda install --file requirements/test.txt
           python -m pip install -r requirements/pip.txt
           python -m pip install . --no-deps
 
+      - name: Install latest diffpy.pdffit2 for Mac
+        if: runner.os == 'macos-latest'
+        run: |
+          conda uninstall diffpy.pdffit2
+          brew install gsl
+          pip install diffpy.pdffit2==1.4.4rc1
+
       - name: Install Xvfb
         if: runner.os == 'Linux'
         run: sudo apt-get install -y xvfb
@@ -53,7 +60,7 @@ jobs:
           export DISPLAY=:99
           Xvfb :99 -screen 0 1024x768x16 &
 
-      - name: Validate test_workflow
+      - name: Validate diffpy.pdfgui
         run: |
           if [ "$RUNNER_OS" == "Linux" ]; then
             export DISPLAY=:99