Set long_description_content_type as it's required now by Pypi

setup.py

@@ -9,20 +9,21 @@
     long_description = file.read()
 
 setup(
-  name             = 'prometheus-pgbouncer-exporter',
-  packages         = ['prometheus_pgbouncer_exporter'],
-  version          = '2.0.2',
-  description      = 'Prometheus exporter for PgBouncer',
-  long_description = long_description,
-  author           = 'Marco Pracucci',
-  author_email     = '[email protected]',
-  url              = 'https://github.com/spreaker/prometheus-pgbouncer-exporter',
-  download_url     = 'https://github.com/spreaker/prometheus-pgbouncer-exporter/archive/2.0.1.tar.gz',
-  keywords         = ['prometheus', 'pgbouncer'],
-  classifiers      = [],
-  python_requires  = ' >= 3',
-  install_requires = ['psycopg2 == 2.7.3.2', 'prometheus_client==0.0.21', 'python-json-logger==0.1.5', 'PyYAML==3.12'],
-  entry_points     = {
+  name                          = 'prometheus-pgbouncer-exporter',
+  packages                      = ['prometheus_pgbouncer_exporter'],
+  version                       = '2.0.2',
+  description                   = 'Prometheus exporter for PgBouncer',
+  long_description              = long_description,
+  long_description_content_type = "text/markdown",
+  author                        = 'Marco Pracucci',
+  author_email                  = '[email protected]',
+  url                           = 'https://github.com/spreaker/prometheus-pgbouncer-exporter',
+  download_url                  = 'https://github.com/spreaker/prometheus-pgbouncer-exporter/archive/2.0.1.tar.gz',
+  keywords                      = ['prometheus', 'pgbouncer'],
+  classifiers                   = [],
+  python_requires               = ' >= 3',
+  install_requires              = ['psycopg2 == 2.7.3.2', 'prometheus_client==0.0.21', 'python-json-logger==0.1.5', 'PyYAML==3.12'],
+  entry_points                  = {
     'console_scripts': [
         'pgbouncer-exporter=prometheus_pgbouncer_exporter.cli:main',
     ]