Lessons learned making a `GIT_EXTERNAL_DIFF`
```
/*
when making a change to a file:
0 renovate/github-cucumber-cucumber-jvm.json
1 /tmp/git-blob-vpKNNS/github-cucumber-cucumber-jvm.json
2 10691ceb2dae54cbf797e9217d197fee0463445b
3 100644
4 /tmp/git-blob-3KM3Xl/github-cucumber-cucumber-jvm.json
5 09656e4c1dffe83df607add0091f6270bb9c5dff
6 100644
when deleting a file
0 renovate/github-DDDEastMidlandsLimited-dddem-blog.json
1 /tmp/git-blob-aBldZ4/github-DDDEastMidlandsLimited-dddem-blog.json
2 6b24e38aa4aac8e00e44ab68e156744138ef6afc
3 100644
4 /dev/null
5 .
6 .
*/
```
issue