Removed unused matrix

Author: Tonye Jack

.github/workflows/check_constraints.yml

@@ -7,7 +7,8 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        os: [ubuntu-latest, macos-latest, windows-latest]
+        os: [ubuntu-latest]
+#        os: [ubuntu-latest, macos-latest, windows-latest]
         python-version: [3.5, 3.6, 3.7, 3.8, pypy3]
 
     services:

README.md

@@ -4,7 +4,7 @@
 [![PyPI - Python Version](https://img.shields.io/pypi/pyversions/django-check-constraint.svg)](https://pypi.org/project/django-check-constraint)
 [![PyPI - Django Version](https://img.shields.io/pypi/djversions/django-check-constraint.svg)](https://docs.djangoproject.com/en/2.2/releases/)
 ![Upload Python Package](https://github.com/jackton1/django-check-constraint/workflows/Upload%20Python%20Package/badge.svg)
-![Create New Release](https://github.com/jackton1/django-check-constraint/workflows/Create%20New%20Release/badge.svg)
+![Create New Release](https://github.com/jackton1/django-check-constraint/workflows/Create%20New%20Release/badge.svg?branch=master&event=push)
 
 
 Extends [Django's Check](https://docs.djangoproject.com/en/3.0/ref/models/options/#constraints) constraint with support for annotations and calling db functions.