【Python】DjangoGirlsTutorial で $ git push heroku master が実行できない

前提・実現したいこと

DjangoGirlsTutorial というサイトに従い、Django の学習を進めているものです。
「デプロイ」という項目で、$ git push heroku master を実行したところ、以下のエラーが発生しました。
お分かりになる方、ご教授願います。

https://djangogirlsjapan.gitbooks.io/workshop_tutorialjp/django_start_project/

発生している問題・エラーメッセージ

Counting objects: 21, done.
Delta compression using up to 4 threads.
Compressing objects: 100% (18/18), done.
Writing objects: 100% (21/21), 6.25 KiB | 2.08 MiB/s, done.
Total 21 (delta 1), reused 0 (delta 0)
remote: Compressing source files... done.
remote: Building source:
remote: 
remote: -----> Python app detected
remote:  !     The latest version of Python 3 is python-3.6.4 (you are using python-3.5.2, which is unsupported).
remote:  !     We recommend upgrading by specifying the latest version (python-3.6.4).
remote:        Learn More: https://devcenter.heroku.com/articles/python-runtimes
remote: -----> Installing python-3.5.2
remote: -----> Installing pip
remote: -----> Installing requirements with pip
remote:        Collecting dj-database-url==0.5.0 (from -r /tmp/build_442f7fd0ab04703a3217b5036f9ca2b0/requirements.txt (line 1))
remote:          Downloading https://files.pythonhosted.org/packages/d4/a6/4b8578c1848690d0c307c7c0596af2077536c9ef2a04d42b00fabaa7e49d/dj_database_url-0.5.0-py2.py3-none-any.whl
remote:        Collecting Django==1.8.19 (from -r /tmp/build_442f7fd0ab04703a3217b5036f9ca2b0/requirements.txt (line 2))
remote:          Downloading https://files.pythonhosted.org/packages/96/b9/b4108da1275dc2ac1bba1e87739cb31b3d44339affb83b0e949fb09c2bef/Django-1.8.19-py2.py3-none-any.whl (6.2MB)
remote:        Collecting gunicorn==19.7.1 (from -r /tmp/build_442f7fd0ab04703a3217b5036f9ca2b0/requirements.txt (line 3))
remote:          Downloading https://files.pythonhosted.org/packages/64/32/becbd4089a4c06f0f9f538a76e9fe0b19a08f010bcb47dcdbfbc640cdf7d/gunicorn-19.7.1-py2.py3-none-any.whl (111kB)
remote:        Collecting whitenoise==3.3.1 (from -r /tmp/build_442f7fd0ab04703a3217b5036f9ca2b0/requirements.txt (line 4))
remote:          Downloading https://files.pythonhosted.org/packages/0c/58/0f309a821b9161d0e3a73336a187d1541c2127aff7fdf3bf7293f9979d1d/whitenoise-3.3.1-py2.py3-none-any.whl
remote:        Collecting psycopg2==2.5.4 (from -r /tmp/build_442f7fd0ab04703a3217b5036f9ca2b0/requirements.txt (line 5))
remote:          Downloading https://files.pythonhosted.org/packages/63/c3/802668cb3cfc2880c2a8364623e7105a0257724a2612bb66ec733aaddb8c/psycopg2-2.5.4.tar.gz (682kB
remote:            Complete output from command python setup.py egg_info:
remote:            running egg_info
remote:            creating pip-egg-info/psycopg2.egg-info
remote:            writing dependency_links to pip-egg-info/psycopg2.egg-info/dependency_links.txt
remote:            writing top-level names to pip-egg-info/psycopg2.egg-info/top_level.txt
remote:            writing pip-egg-info/psycopg2.egg-info/PKG-INFO
remote:            writing manifest file 'pip-egg-info/psycopg2.egg-info/SOURCES.txt'
remote:            Error: could not determine PostgreSQL version from '10.3'
remote:            
remote:            ----------------------------------------
remote:        Command "python setup.py egg_info" failed with error code 1 in /tmp/pip-build-vrf2s3jv/psycopg2/
remote:  !     Push rejected, failed to compile Python app.
remote: 
remote:  !     Push failed
remote: Verifying deploy...
remote: 
remote: !	Push rejected to djangogirlsblog-y.
remote: 
To https://git.heroku.com/djangogirlsblog-yance.git
 ! [remote rejected] master -> master (pre-receive hook declined)
error: failed to push some refs to 'https://git.heroku.com/djangogirlsblog-y.git'

該当のソースコード

(myvenv) MacBook-Pro:djangogirls yy$ git push heroku master

試したこと

上記URLに従って写経していました。

(myvenv) MacBook-Pro:djangogirls yy$ pyenv install 3.6.4
python-build: use openssl from homebrew
python-build: use readline from homebrew
Downloading Python-3.6.4.tar.xz...
-> https://www.python.org/ftp/python/3.6.4/Python-3.6.4.tar.xz
Installing Python-3.6.4...
python-build: use readline from homebrew
Installed Python-3.6.4 to /Users/yy/.pyenv/versions/3.6.4

python3.6.4にアップグレードしましたが同様のエラーが発生しました。