Support adding `Authorization` HTTP headers through the `RUSTUP_AUTHO… #3792

Job	Run time
build-macos-aarch64 (release, aarch64-apple-darwin)	4m 27s
build-macos-aarch64 (dev, aarch64-apple-darwin)	13m 42s
build-macos-x86_64 (release, x86_64-apple-darwin)	9m 43s
build-windows-pr (release, x86_64-pc-windows-gnu)	9m 44s
doc	9s
build-windows-pr (release, aarch64-pc-windows-msvc)	6m 57s
build-windows-pr (dev, aarch64-pc-windows-msvc)	25m 41s
check	3m 8s
build-windows-pr (release, x86_64-pc-windows-msvc)	6m 47s
build-all-features (ubuntu-latest, x86_64-unknown-linux-gnu)	8m 2s
build-macos-x86_64 (dev, x86_64-apple-darwin)	16m 34s
build-linux-pr (release, x86_64-unknown-linux-gnu)	6m 0s
build-linux-pr (release, aarch64-unknown-linux-gnu)	5m 49s
build-linux-pr (release, armv7-unknown-linux-gnueabihf)	4m 55s
build-linux-pr (dev, armv7-unknown-linux-gnueabihf)	3m 27s
build-linux-pr (dev, aarch64-unknown-linux-gnu)	9m 25s
build-windows-pr (dev, x86_64-pc-windows-gnu)	13m 29s
build-windows-pr (dev, x86_64-pc-windows-msvc)	22m 20s
build-linux-pr (dev, aarch64-linux-android)	3m 22s
build-all-features (windows-latest, x86_64-pc-windows-msvc)	19m 59s
build-linux-pr (release, aarch64-linux-android)	4m 57s
build-linux-pr (dev, x86_64-unknown-linux-gnu)	8m 48s
build-freebsd-main	0s
build-linux-main	0s
build-windows-main	0s
build-freebsd-stable	0s
build-windows-stable	0s
build-linux-stable	0s
conclusion	3s
	3h 27m 28s

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