Add reading of PR title and body from branch config

[corg]

Examples of PR title and body, both optional:

# .pr-train.yml

trains:
  Super duper train:
    - oleg-improve-readme:
        title: Readme improvements
        body: Now readme is the best
    - oleg-other-improvements:
    - oleg-improvements-combined:
        combined: true
        title: The big one # Works for combined branch too! And body is optional.

If title is not found in branch config, it will be read from git log just as before, along with body.

Resolves #6.

[corg]

Hi @realyze, I can't assign you as a reviewer in this repo so you might have missed this one. When you have a chance, can you please take a look at this? Thanks!

[kjun9]

Hello 👋 I realise this is 3 years old... but just wondering if there was a reason not to go ahead with this? I was considering forking and implementing something similar and came across this 😄

[realyze]

Yikes, three years 🙈 I'm so sorry for missing this.

So how would it work after the PR is already created and you want to update the description/title? What would be the source of truth? Would the config only be used when the PR is created?

I'm also a little bit hesitant to specify description in config like this. Usually you want a PR description to be a but more...uh, descriptive and not very short?

[kjun9]

Hey, thanks for getting back to me! Yeah I'm not sure either now that I think about it actually

So how would it work after the PR is already created and you want to update the description/title? What would be the source of truth? Would the config only be used when the PR is created?

I was thinking that the yaml would always be the source of truth, so that whenever you want to update the title/description you do it via the yaml file and push. I guess the motivation for me was the idea of doing more of managing PR trains in my IDE.

But yeah it wouldn't be great if someone forgot they updated something on the UI instead and then pushed the old description from their yaml. Maybe by default it's only used when the PR is first created, and only overwrites existing stuff if another cli option is specified 🤷

I'm also a little bit hesitant to specify description in config like this. Usually you want a PR description to be a but more...uh, descriptive and not very short?

Yeah that's true, not the greatest experience to write markdown in a yaml config field