fix: Make RECEIPT_HOME variable XDG compliant

[brennanfee]

The setting of RECEIPT_HOME using "${HOME}/.config" will fail for users who move their config folder elsewhere using XDG_CONFIG_HOME. Both dash and bash (the usual interpreters for /bin/sh) both support parameter substitution.

[Gankra]

(failures are just needing to run cargo test, cargo insta review --accept, i can do that for you)

[Gankra]

Oh rad, ty. We might need to port this to axoupdater as well to make sure everything that cares about receipts agrees and can reliably find this.

Hmm, also actually now that I think about this there's a bit of a migration concern... ok right I think migration handling can just exist in axoupdater. The install script itself is write-only, so doesn't need to care if it changes location.

[Gankra]

Oh haha, because this PR is from the main branch of your fork I'm not actually allowed to push to it 😅

[brennanfee]

I can move this to another branch, but I believe I would need to re-submit a PR? I don't think we can edit the branch the PR comes from. What would be your preference?

[brennanfee]

Also, I'd be happy to take a look at axoupdater. I have a lot of bash scripting experience and can spot XDG "errors" like a hawk. However, I'm new to rust so will need a fair bit of support from you guys to make sure I'm not messing something up.

[Gankra]

Sorry for the delay this PR is great and is approved but had some interesting logistics.

So what needs to happen is:

• merge feat: support XDG_CONFIG_HOME for receipts axoupdater#171
• release axoupdater
• implement Add "minimum supported axoupdater version" checks #1392
• set the minimum axoupdater to the above released version
• then merge this PR

[Gankra]

For "don't count your chickens before they hatch" reasons ideally we impl #1392 before we merge/release axoupdater.

[ashleygwilliams]

now that #1392 is merged we are closer to getting this merged. the current plan is to release this is the release after next (which will contain the minimum viable version work)