Drop support for Python 3.5 (end-of-life)

.github/workflows/test.yml

@@ -7,7 +7,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest, macos-latest, windows-latest]
-        python-version: [3.5, 3.6, 3.7, 3.8, '3.9.0-alpha - 3.9', pypy3]
+        python-version: [3.6, 3.7, 3.8, '3.9.0-alpha - 3.9', pypy3]
     steps:
       - uses: actions/checkout@v2
       - uses: actions/setup-python@v2

setup.py

@@ -76,7 +76,7 @@ setup(
     extras_require={"test": tests_require,
                     "bcrypt": ["passlib[bcrypt]", "bcrypt"]},
     keywords=["calendar", "addressbook", "CalDAV", "CardDAV"],
-    python_requires=">=3.5.2",
+    python_requires=">=3.6.0",
     classifiers=[
         "Development Status :: 5 - Production/Stable",
         "Environment :: Console",
@@ -86,7 +86,6 @@ setup(
         "License :: OSI Approved :: GNU General Public License (GPL)",
         "Operating System :: OS Independent",
         "Programming Language :: Python :: 3",
-        "Programming Language :: Python :: 3.5",
         "Programming Language :: Python :: 3.6",
         "Programming Language :: Python :: 3.7",
         "Programming Language :: Python :: 3.8",