Update README.md

[blackerking]

Adding information for using this docker behind a https proxy, like swag.

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

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[LinuxServer-CI]

I am a bot, here are the test results for this PR:
https://ci-tests.linuxserver.io/lspipepr/airsonic-advanced/11.1.4-pkg-87945444-dev-7b190c954152ff946c2903f72afec539f208e6e6-pr-30/index.html
https://ci-tests.linuxserver.io/lspipepr/airsonic-advanced/11.1.4-pkg-87945444-dev-7b190c954152ff946c2903f72afec539f208e6e6-pr-30/shellcheck-result.xml

Tag	Passed
amd64-11.1.4-pkg-87945444-dev-7b190c954152ff946c2903f72afec539f208e6e6-pr-30	✅
arm64v8-11.1.4-pkg-87945444-dev-7b190c954152ff946c2903f72afec539f208e6e6-pr-30	✅

[LinuxServer-CI]

I am a bot, here are the test results for this PR:
https://ci-tests.linuxserver.io/lspipepr/airsonic-advanced/11.1.4-pkg-67f245d7-dev-f048b35665bbb9b60d50b2db369681cd37a8be74-pr-30/index.html
https://ci-tests.linuxserver.io/lspipepr/airsonic-advanced/11.1.4-pkg-67f245d7-dev-f048b35665bbb9b60d50b2db369681cd37a8be74-pr-30/shellcheck-result.xml

Tag	Passed
amd64-11.1.4-pkg-67f245d7-dev-f048b35665bbb9b60d50b2db369681cd37a8be74-pr-30	✅
arm64v8-11.1.4-pkg-67f245d7-dev-f048b35665bbb9b60d50b2db369681cd37a8be74-pr-30	❌