unpin build dep versions

.github/workflows/test_build.yml

@@ -32,11 +32,11 @@ jobs:
 
       - name: Installing build dependencies
         run: |
-          pip install markupsafe==2.0.1
-          pip install jupyter==1.0.0
-          pip install -U jupyter-book==1.0.0
-          pip install nbmake==1.5.3
-          pip install pytest-xdist==3.5.0
+          pip install markupsafe
+          pip install jupyter
+          pip install -U jupyter-book
+          pip install nbmake
+          pip install pytest-xdist
         
       - name: Printing environment
         run: pip freeze