requirements: install ipython for ishell to work

requirements.txt

@@ -94,6 +94,25 @@ gunicorn==21.2.0
 infrae.cache==1.0.1
   beaker==1.12.1
   repoze.lru==0.7
+ipython==8.14.0
+  backcall==0.2.0
+  decorator==5.1.1
+  jedi==0.19.0
+    parso==0.8.3
+  matplotlib-inline==0.1.6
+    traitlets==5.9.0
+  pexpect==4.8.0
+    ptyprocess==0.7.0
+  pickleshare==0.7.5
+  prompt-toolkit==3.0.38
+    wcwidth==0.2.6
+  pygments==2.15.1
+  stack-data==0.6.2
+    asttokens==2.2.1
+      six==1.16.0
+    executing==1.2.0
+    pure-eval==0.2.2
+  traitlets==5.9.0
 markdown==3.4.3
 msgpack==1.0.5
 mysqlclient==2.1.1