Fix current installation of package

(current installation leads to 502 error with
sqlalchemy.cimmutabledict.immutabledict' object has no attribute 'setdefault'
exception).

Workaround SQLA 4.x backward incompatible change

manifest.json

@@ -7,7 +7,7 @@
         "fr": "Une application web de comptes partagés à plusieurs"
     },
     "url": "http://ihatemoney.org/",
-    "version": "4.1.5~ynh1",
+    "version": "4.1.5~ynh2",
     "license": "free",
     "maintainer": {
         "name": "Jocelyn Delalande",

scripts/_common.sh

@@ -40,10 +40,13 @@ init_virtualenv () {
 }
 
 pip_install () {
+    # SQLAlchemy requirement is workaround https://github.com/pallets/flask-sqlalchemy/issues/910
+    # Might be removed later when IHM dependency set will no longer prevent working installation.
     /opt/yunohost/ihatemoney/venv/bin/pip install --upgrade \
      'gunicorn>=19.3.0' \
      'PyMySQL>=0.9,<0.10' \
      'ihatemoney>=4,<5' \
+     'SQLAlchemy<1.4' \
 
 }