Aiida 2.0 (#102)

* Relax requirements.
* Add missing requirement (Markdown).
* Update setup.cfg
* Remove support of Python 3.7

setup.cfg

@@ -15,7 +15,6 @@ classifiers =
     License :: OSI Approved :: MIT License
     Programming Language :: Python :: 3
     Programming Language :: Python :: 3 :: Only
-    Programming Language :: Python :: 3.7
     Programming Language :: Python :: 3.8
     Programming Language :: Python :: 3.9
     Programming Language :: Python :: 3.10
@@ -25,12 +24,13 @@ project_urls =
 [options]
 packages = find:
 install_requires =
+    Jinja2>=2.11.3,<4
+    Markdown>=3.4
     aiidalab>=v21.10.2
-    ipython~=7.25
+    ipython~=7.0
     ipywidgets~=7.6
-    jinja2~=2.11
     traitlets~=5.0
-python_requires = >=3.7
+python_requires = >=3.8
 
 [options.extras_require]
 pre_commit =