Update default conf with new http2 directive

[thespad]

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

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Description:

Benefits of this PR and context:

How Has This Been Tested?

Source / References:

[LinuxServer-CI]

I am a bot, here are the test results for this PR:
https://ci-tests.linuxserver.io/lspipepr/speedtest-tracker/v0.19.0-pkg-20572238-dev-b2b296f122be6071e3afe8cba5fa34cf54602ad7-pr-16/index.html
https://ci-tests.linuxserver.io/lspipepr/speedtest-tracker/v0.19.0-pkg-20572238-dev-b2b296f122be6071e3afe8cba5fa34cf54602ad7-pr-16/shellcheck-result.xml

Tag	Passed
amd64-v0.19.0-pkg-20572238-dev-b2b296f122be6071e3afe8cba5fa34cf54602ad7-pr-16	✅
arm64v8-v0.19.0-pkg-20572238-dev-b2b296f122be6071e3afe8cba5fa34cf54602ad7-pr-16	✅

[LinuxServer-CI]

I am a bot, here are the test results for this PR:
https://ci-tests.linuxserver.io/lspipepr/speedtest-tracker/v0.19.0-pkg-20572238-dev-a3a40f0510b683fcfcbe7da50462c0287dfcaa4d-pr-16/index.html
https://ci-tests.linuxserver.io/lspipepr/speedtest-tracker/v0.19.0-pkg-20572238-dev-a3a40f0510b683fcfcbe7da50462c0287dfcaa4d-pr-16/shellcheck-result.xml

Tag	Passed
amd64-v0.19.0-pkg-20572238-dev-a3a40f0510b683fcfcbe7da50462c0287dfcaa4d-pr-16	✅
arm64v8-v0.19.0-pkg-20572238-dev-a3a40f0510b683fcfcbe7da50462c0287dfcaa4d-pr-16	✅

[LinuxServer-CI]

I am a bot, here are the test results for this PR:
https://ci-tests.linuxserver.io/lspipepr/speedtest-tracker/v0.19.0-pkg-20572238-dev-b32236ad6526d408d6dfce65c0038aa3ac153d08-pr-16/index.html
https://ci-tests.linuxserver.io/lspipepr/speedtest-tracker/v0.19.0-pkg-20572238-dev-b32236ad6526d408d6dfce65c0038aa3ac153d08-pr-16/shellcheck-result.xml

Tag	Passed
amd64-v0.19.0-pkg-20572238-dev-b32236ad6526d408d6dfce65c0038aa3ac153d08-pr-16	✅
arm64v8-v0.19.0-pkg-20572238-dev-b32236ad6526d408d6dfce65c0038aa3ac153d08-pr-16	✅