MAINT: Remove Python 3.5 support (#1948)

* MAINT: Remove Python 3.5 support

* Delete .travis.yml

Co-authored-by: bl-ue <bl-ue@users.noreply.github.com>
diff --git a/.travis.yml b/.travis.yml
deleted file mode 100644
index 94c129b..0000000
--- a/.travis.yml
+++ /dev/null
@@ -1,48 +0,0 @@
-# vim ft=yaml
-# Multiple lines can be made a single "virtual line" because of how Travis
-# munges each line before executing it to print out the exit status.  It's okay
-# for it to be on multiple physical lines, so long as you remember: - There
-# can't be any leading "-"s - All newlines will be removed, so use ";"s
-
-dist: focal
-language: python
-cache: pip
-python:
-  - 3.5
-  - 3.6
-  - 3.7
-  - 3.8
-env:
-  REQUIRE_ASPELL=true
-
-addons:
-  apt:
-    packages:
-      - libaspell-dev
-      - aspell-en
-
-before_install:
-    - source tools/travis_tools.sh
-    - SRC_DIR=$PWD
-    - cd ~
-    - virtualenv --python=python venv
-    - source venv/bin/activate
-    - python --version  # just to check
-    - pip install -U pip wheel # upgrade to latest pip find 3.5 wheels; wheel to avoid errors
-    - retry pip install codecov chardet "setuptools!=47.2.0" docutils
-    - retry pip install aspell-python-py3
-    - cd $SRC_DIR
-    - pip install -e ".[dev]" # install the codespell dev packages
-
-install:
-    - python setup.py install
-
-script:
-    - codespell --help
-    - make check
-    - codespell --check-filenames --skip="./.git/*,*.pyc,./codespell_lib/tests/test_basic.py,./codespell_lib/data/*,./example/code.c,./build/lib/codespell_lib/tests/test_basic.py,./build/lib/codespell_lib/data/*"
-    # this file has an error
-    - "! codespell codespell_lib/tests/test_basic.py"
-
-after_success:
-    - codecov
diff --git a/README.rst b/README.rst
index de9f4be..dab29a8 100644
--- a/README.rst
+++ b/README.rst
@@ -23,7 +23,7 @@
 Requirements
 ------------
 
-Python 3.5 or above.
+Python 3.6 or above.
 
 Installation
 ------------
@@ -134,10 +134,10 @@
 
    Note that there isn't a comma at the end of the line. The last argument is
    treated as the reason why a suggestion cannot be automatically applied.
-   
+
    There can also be multiple suggestions but any automatic fix will again be
    disabled::
-   
+
        clas->class, clash, disabled because of name clash in c++
 
 Development Setup
diff --git a/setup.py b/setup.py
index afbe083..9271fde 100755
--- a/setup.py
+++ b/setup.py
@@ -43,7 +43,7 @@
                        'Operating System :: Unix',
                        'Operating System :: MacOS'],
           platforms='any',
-          python_requires='>=3.5',
+          python_requires='>=3.6',
           packages=[
               'codespell_lib',
               'codespell_lib.data',