Drop python 2.7 and 3.5 support

Author: p1c2u

.github/workflows/python-test.yml

@@ -14,7 +14,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: [2.7, 3.5, 3.6, 3.7, 3.8, 3.9]
+        python-version: [3.6, 3.7, 3.8, 3.9]
       fail-fast: false
     steps:
       - uses: actions/checkout@v2

.travis.yml

@@ -2,8 +2,6 @@ language: python
 sudo: false
 matrix:
   include:
-  - python: 2.7
-  - python: 3.5
   - python: 3.6
   - python: 3.7
   - python: 3.8

pyproject.toml

@@ -23,9 +23,7 @@ classifiers = [
     "Intended Audience :: Developers",
     "Topic :: Software Development :: Libraries :: Python Modules",
     "Operating System :: OS Independent",
-    "Programming Language :: Python :: 2.7",
     "Programming Language :: Python :: 3",
-    "Programming Language :: Python :: 3.5",
     "Programming Language :: Python :: 3.6",
     "Programming Language :: Python :: 3.7",
     "Programming Language :: Python :: 3.8",