Fix Heroku builds by locking python-poetry-buildpack version (#1871)

* Fix Heroku builds by locking python-poetry-buildpack version

* Keep local dev POETRY_VERSION in sync with Heroku config var

Makefile

@@ -7,8 +7,9 @@ deps:
 	# Install node: https://github.com/nodesource/distributions/blob/master/README.md#deb		
 	curl -fsSL https://deb.nodesource.com/setup_16.x | sudo -E bash -
 	sudo apt-get install -y nodejs
-	# Install poetry: https://python-poetry.org/docs/master/#osx--linux--bashonwindows-install-instructions 
-	curl -sSL https://install.python-poetry.org | POETRY_VERSION=1.1.13 python3.8 -
+	# Install poetry: https://python-poetry.org/docs/master/#osx--linux--bashonwindows-install-instructions
+	# Keep the local dev POETRY_VERSION in sync with the Heroku config var
+	curl -sSL https://install.python-poetry.org | POETRY_VERSION=1.1.15 python3.8 -
 	sudo npm install -g yarn
 	sudo apt install -y postgresql
 	sudo systemctl start postgresql

app.json

@@ -2,7 +2,9 @@
   "addons": ["heroku-postgresql:hobby-free"],
   "buildpacks": [
     { "url": "heroku/nodejs" },
-    { "url": "https://github.com/moneymeets/python-poetry-buildpack.git" },
+    {
+      "url": "https://github.com/moneymeets/python-poetry-buildpack.git#0bbaf48423f0caac527e185b1517abac1610dc46"
+    },
     { "url": "heroku/python" },
     { "url": "heroku-community/cli" }
   ],