Prepare travis for upcoming poetry 1.0 release
Prepare travis for upcoming poetry 1.0 release

The poetry version command will change in poetry 1.0 (see sdispater/poetry#1191). Without any argument, it won't bump the version anymore but instead just print the current version. This will break the current travis before_install. Let's pin poetry to ~0.12.17 for now and change it once poetry v1.0 releases.
maebert/jrnl