added pip install -U pip back to general travis build - pip 20.2 should work

.travis.yml

@@ -99,7 +99,7 @@ matrix:
       env: PATH=/c/Python37:/c/Python37/Scripts:$PATH
 before_install:
   - python --version
-  # - pip install -U pip
+  - pip install -U pip
   - pip install -U pytest
   - pip install codecov
   - pip install pymongo

pytest.ini

@@ -0,0 +1,13 @@
+[pytest]
+testpaths =
+    tests
+    cachier
+norecursedirs=dist build .tox
+addopts =
+    # --doctest-modules
+    --cov=cachier
+    --cov-report term
+    --cov-report xml:cov.xml
+    -r a
+    -v
+    -s

tox.ini

@@ -1,36 +0,0 @@
-[tox]
-envlist =
-    py27
-    py35
-    py36
-# recreate = True
-
-[testenv]
-deps =
-    ; equivalent to pip -e .[test]
-    -e{toxinidir}[test]
-    ;-r{toxinidir}/tools/pip-requires
-    ;-r{toxinidir}/tools/test-require
-commands=py.test  # or 'nosetests' or ...
-usedevelop = true
-
-# [testenv:doctesting]
-# basepython = python
-# usedevelop=True
-# skipsdist=True
-# commands=
-#     pytest --doctest-modules --pyargs _pytest
-
-[pytest]
-testpaths =
-    tests
-    cachier
-norecursedirs=dist build .tox
-addopts =
-    # --doctest-modules
-    --cov=cachier
-    --cov-report term
-    --cov-report xml:cov.xml
-    -r a
-    -v
-    -s