use good english

setup.py

@@ -13,7 +13,7 @@ setup(
     packages=find_packages(),
     include_package_data=True,
     license="AGPLv3",
-    description="Postfix' Transport Encryption under Control of the User",
+    description="Postfix's Transport Encryption under Control of the User",
     long_description=README,
     url="https://posttls.com/",
     author="Hendrik Suenkler",