Bump to version v21.07.0b4. (#100)

setup.cfg

@@ -1,6 +1,6 @@
 [metadata]
 name = aiidalab-qe
-version = 20.12.0
+version = 21.07.0b4
 author = The AiiDAlab team
 author_email = [email protected]
 description = Package for the AiiDAlab QE app
@@ -20,8 +20,8 @@ python_requires = >=3.7
 install_requires =
     aiida-core~=1.0
     aiida-quantumespresso~=3.4
-    aiidalab-qe-workchain @ https://github.com/aiidalab/aiidalab-qe/raw/develop/src/dist/aiidalab_qe_workchain-1.0-py3-none-any.whl
-    aiidalab-widgets-base~=1.0b
+    aiidalab-qe-workchain @ https://github.com/aiidalab/aiidalab-qe/raw/v21.07.0b3/src/dist/aiidalab_qe_workchain-1.0-py3-none-any.whl
+    aiidalab-widgets-base~=1.0.0b19
     widget_bandsplot~=0.2.1
 
 [options.extras_require]