- Bumped patch version.

script listed.
- Bumped patch version.
- Added pre-commit hooks to test the shell-lint script added.

variables set).
- Bump minor version.

- Cache pip and pre-commit in TravisCI.

.pre-commit-hooks.yaml, update pre-commit-config.yaml accordingly.
- Set pre-commit hooks by version tag instead of hash.
- Bump minor version.