Bump version to 0.4.39 #3518

Job	Run time
check-docs	22s
cross-targets (x86_64-unknown-illumos)	1m 10s
alternative_targets (ubuntu-latest, wasm32-unknown-emscripten)	16s
cross-tests (ubuntu-latest)	1m 53s
features_check (ubuntu-latest)	4m 7s
alternative_targets (ubuntu-latest, aarch64-apple-ios)	12s
no_std (ubuntu-latest, thumbv6m-none-eabi)	17s
alternative_targets (ubuntu-latest, aarch64-linux-android)	10s
no_std (ubuntu-latest, x86_64-fortanix-unknown-sgx)	24s
rust_msrv (ubuntu-latest)	1m 40s
rust_versions (ubuntu-latest, stable)	1m 2s
rust_versions (ubuntu-latest, beta)	1m 26s
test_wasi (ubuntu-latest, wasm32-wasi)	34s
test_wasm (ubuntu-latest)	27s
rust_versions (ubuntu-latest, nightly)	1m 6s
timezones (ubuntu-latest, ACST-9:30)	1m 18s
timezones (ubuntu-latest, EST4)	1m 36s
timezones (ubuntu-latest, UTC0)	1m 30s
timezones (ubuntu-latest, Asia/Katmandu)	1m 23s
timezones (macos-latest, ACST-9:30)	33s
timezones (macos-latest, EST4)	32s
timezones (macos-latest, UTC0)	34s
timezones (macos-latest, Asia/Katmandu)	36s
timezones (windows-latest, ACST-9:30)	2m 29s
timezones (windows-latest, EST4)	1m 40s
timezones (windows-latest, UTC0)	2m 54s
timezones (windows-latest, Asia/Katmandu)	2m 43s
	32m 54s

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