Leave curl in image

[chessmango]

---

• I have read the contributing guideline and understand that I have made the correct modifications

---

Description:

This re-adds/avoids deleting the curl package from the final image, which matches version 1.xx

Benefits of this PR and context:

curl is a nice-to-have to enable health checks and have downstream services start when socket-proxy is fully ready and Docker's _ping endpoint is available. Not sure how LSIO feels about prescriptive guidance, but I could also add some extras to the readme about how to do this with plain Docker and Docker Compose.

How Has This Been Tested?

Built a container 🤷 not much change

Source / References:

[LinuxServer-CI]

I am a bot, here are the test results for this PR:
https://ci-tests.linuxserver.io/lspipepr/socket-proxy/3.0.9-r0-pkg-3ad5f7cf-dev-297951a8c1c98f4238a2f628b7c53b5f46973d9a-pr-31/index.html
https://ci-tests.linuxserver.io/lspipepr/socket-proxy/3.0.9-r0-pkg-3ad5f7cf-dev-297951a8c1c98f4238a2f628b7c53b5f46973d9a-pr-31/shellcheck-result.xml

Tag	Passed
amd64-3.0.9-r0-pkg-3ad5f7cf-dev-297951a8c1c98f4238a2f628b7c53b5f46973d9a-pr-31	✅
arm64v8-3.0.9-r0-pkg-3ad5f7cf-dev-297951a8c1c98f4238a2f628b7c53b5f46973d9a-pr-31	✅

[chessmango]

Figured I'd take a security-conscious approach here for my own stuff, and just switched to wget, which is less involved.
This way curl stays out of the image and healthchecks are still possible. My resulting healthcheck config (in compose), for anyone interested:

    healthcheck:
      test:
        - CMD
        - wget
        - --quiet
        - --tries=1
        - --timeout=1
        - --spider
        - http://localhost:2375/_ping

The offer to document health checks still stands, in case that's relevant to other interests.