Update docker-compose setup

[pkqk]

• Simplify the copying of go files into docker context when building the gateway
• Pin the example services to golang:1.17 and node:18

[codecov-commenter]

Codecov Report

Base: 70.70% // Head: 70.74% // Increases project coverage by +0.03% :tada:

Coverage data is based on head (8c8f08f) compared to base (8b8e104). Patch has no changes to coverable lines.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #173 +/- ## ========================================== + Coverage 70.70% 70.74% +0.03% ========================================== Files 26 26 Lines 2690 2690 ========================================== + Hits 1902 1903 +1 + Misses 665 664 -1 Partials 123 123 ``` | [Impacted Files](https://codecov.io/gh/movio/bramble/pull/173?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=movio) | Coverage Δ | | |---|---|---| | [auth.go](https://codecov.io/gh/movio/bramble/pull/173/diff?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=movio#diff-YXV0aC5nbw==) | `89.17% <0.00%> (+0.63%)` | :arrow_up: | Help us with your feedback. Take ten seconds to tell us [how you rate us](https://about.codecov.io/nps?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=movio). Have a feature suggestion? [Share it here.](https://app.codecov.io/gh/feedback/?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=movio)

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