ENH Handle TLN commit prefix

[emteknetnz]

Issue silverstripe/.github#135

There's also an additional commit in here to disable the twig caching which is annoying as it requires the user to rm -rf /tmp/cow/twig/cache in order to get the twig template changes. Given this is so easy to miss it may mean we accidentally leave out the translation commits in a changelog in the future. There is seemingly zero performance difference with the caching disabled

The test this I created mock 5.1.1 release - I made this a patch release to ensure I didn't accidentally create new 5.2 branches

• ensure cow .env file has DEV_MODE=1
• cow release:create -vvv 5.1.1 silverstripe/recipe-kitchen-sink
• cow release:plan -vvv 5.1.1 silverstripe/recipe-kitchen-sink
• Update the readme in framework and add a commit 'TLN My translation commit'
• cow release:changelog -vvv --skip-fetch-tags --include-other-changes --include-upgrade-only 5.1.1 silverstripe/recipe-kitchen-sink

[GuySartorelli]

LGTM