Print MyST version while building in Actions (#40)

Print Myst version while building the website in GitHub Actions for
future reference.

Author: santisoler

.github/workflows/build.yml

@@ -25,10 +25,13 @@ jobs:
         with:
           node-version: '20'
 
-      - name: Install Myst
+      - name: Install MyST
         run: |
           npm install -g mystmd
 
+      - name: Print MyST version
+        run: myst --version
+
       - name: Build website as static HTML
         run: |
           echo "Building MyST website using BASE_URL=" $BASE_URL