Add option for commit message template

[htgoebel]

The commit messages generated by pyup do not match the commit message requirements for one of my projects. Please add an option to specify the commit message. e.g.

# Configure the commit message template
# default: "Update ${packagename} from ${old_version} to ${new_version}"
# allowed variables: packagename, old_version, new_version
commit_message_template: "Requirements: Push ${packagename} to ${new_version}"

[kevinkjt2000]

Having this feature would certainly help when it comes to automated semantic versioning.

[martinm82]

Would be really great as right now the integration with the semantic pull requests app is causing problems due to wrong PR titles.

https://github.com/apps/semantic-pull-requests

[rafaelpivato]

This should be available with next release thanks to @Kaligule

[Kaligule]

@rafaelpivato Very cool, glad to have helped. Do you know when that release might happen?

[rafaelpivato]

In the next few days we should be releasing.

[Kaligule]

@rafaelpivato Any updates on the release? It has been over a month now.

[rafaelpivato]

Thanks for the heads-up, @Kaligule

Just released version 1.1.2

[Kaligule]

@rafaelpivato Thanks :) Can you point me to a place where I can update the documentation about this new feature? As mentioned in the pull request:

I would like to document the new options, but I couldn't find the place to do it other then commit-message and PR-description.

[rafaelpivato]

At this moment the README is the best place as RTD build is pretty outdated.