build: Pin to specific versions of Python packages we install from PyPI in Travis

practicalswift · practicalswift · commit ee0b7c4e8a1e · 2018-10-16T13:48:16.000+02:00
diff --git a/.travis/lint_04_install.sh b/.travis/lint_04_install.sh
@@ -7,4 +7,4 @@
 export LC_ALL=C
 
 travis_retry pip install codespell==1.13.0
-travis_retry pip install flake8
+travis_retry pip install flake8==3.5.0
