tox: Add tox-pip-version

This is needed to upgrade pip so it can install PyQt 5.14.1 manylinux2014
wheels.

misc/requirements/requirements-tox.txt

@@ -8,5 +8,6 @@ pyparsing==2.4.6
 six==1.13.0
 toml==0.10.0
 tox==3.14.3
+tox-pip-version==0.0.6
 tox-venv==0.4.0
 virtualenv==16.7.9

misc/requirements/requirements-tox.txt-raw

@@ -1,2 +1,3 @@
 tox
 tox-venv
+tox-pip-version

tox.ini

@@ -22,6 +22,7 @@ basepython =
     py36: {env:PYTHON:python3.6}
     py37: {env:PYTHON:python3.7}
     py38: {env:PYTHON:python3.8}
+pip_version = pip
 deps =
     -r{toxinidir}/requirements.txt
     -r{toxinidir}/misc/requirements/requirements-tests.txt
@@ -69,6 +70,7 @@ deps =
 [testenv:misc]
 ignore_errors = true
 basepython = {env:PYTHON:python3}
+pip_version = pip
 # For global .gitignore files
 passenv = HOME
 deps =
@@ -80,6 +82,7 @@ commands =
 
 [testenv:vulture]
 basepython = {env:PYTHON:python3}
+pip_version = pip
 deps =
     -r{toxinidir}/requirements.txt
     -r{toxinidir}/misc/requirements/requirements-vulture.txt
@@ -90,6 +93,7 @@ commands =
 
 [testenv:vulture-pyqtlink]
 basepython = {env:PYTHON:python3}
+pip_version = pip
 deps =
     -r{toxinidir}/requirements.txt
     -r{toxinidir}/misc/requirements/requirements-vulture.txt
@@ -100,6 +104,7 @@ commands =
 
 [testenv:pylint]
 basepython = {env:PYTHON:python3}
+pip_version = pip
 ignore_errors = true
 passenv =
 deps =
@@ -113,6 +118,7 @@ commands =
 
 [testenv:pylint-pyqtlink]
 basepython = {env:PYTHON:python3}
+pip_version = pip
 ignore_errors = true
 passenv =
 deps =
@@ -126,6 +132,7 @@ commands =
 
 [testenv:pylint-master]
 basepython = {env:PYTHON:python3}
+pip_version = pip
 passenv = {[testenv:pylint]passenv}
 deps =
     -r{toxinidir}/requirements.txt
@@ -138,6 +145,7 @@ commands =
 
 [testenv:flake8]
 basepython = {env:PYTHON:python3}
+pip_version = pip
 passenv =
 deps =
     -r{toxinidir}/requirements.txt
@@ -147,6 +155,7 @@ commands =
 
 [testenv:pyroma]
 basepython = {env:PYTHON:python3}
+pip_version = pip
 passenv =
 deps =
     -r{toxinidir}/misc/requirements/requirements-pyroma.txt
@@ -155,6 +164,7 @@ commands =
 
 [testenv:check-manifest]
 basepython = {env:PYTHON:python3}
+pip_version = pip
 passenv =
 deps =
      -r{toxinidir}/misc/requirements/requirements-check-manifest.txt
@@ -163,6 +173,7 @@ commands =
 
 [testenv:docs]
 basepython = {env:PYTHON:python3}
+pip_version = pip
 whitelist_externals = git
 passenv = TRAVIS TRAVIS_PULL_REQUEST
 deps =
@@ -175,6 +186,7 @@ commands =
 
 [testenv:pyinstaller]
 basepython = {env:PYTHON:python3}
+pip_version = pip
 passenv = APPDATA HOME
 deps =
     -r{toxinidir}/requirements.txt
@@ -194,6 +206,7 @@ commands = eslint --color --report-unused-disable-directives .
 
 [testenv:mypy]
 basepython = {env:PYTHON:python3}
+pip_version = pip
 passenv = TERM
 deps =
     -r{toxinidir}/requirements.txt
@@ -206,6 +219,7 @@ commands =
 
 [testenv:sphinx]
 basepython = {env:PYTHON:python3}
+pip_version = pip
 passenv =
 usedevelop = true
 deps =