Add v0.8.11 changelog #405

Job	Run time
Test (ubuntu-latest)	41s
Test (macos-latest)	1m 2s
Test (windows-latest)	1m 45s
CheckTargets	1m 25s
Check (aarch64-apple-ios)	28s
Check (aarch64-apple-tvos)	29s
Clippy	8s
Check (aarch64-unknown-openbsd)	28s
Check (arm64_32-apple-watchos)	31s
Docs	5s
Check (armv7-sony-vita-newlibeabihf)	1m 0s
MinimalVersions (ubuntu-latest)	21s
Check (sparcv9-sun-solaris)	28s
MinimalVersions (macos-latest)	34s
Check (x86_64-pc-solaris)	32s
MinimalVersions (windows-latest)	45s
Check (x86_64-unknown-dragonfly)	43s
Check (x86_64-unknown-openbsd)	29s
MSRV (ubuntu-latest)	13s
Nightly	23s
MSRV (macos-latest)	26s
MSRV (windows-latest)	28s
Rustfmt	7s
Sanitizer (address)	56s
TestPoll	43s
Sanitizer (leak)	47s
Sanitizer (memory)	1m 44s
Sanitizer (thread)	52s
TestWakerPipe	35s
Passed	1s
	19m 9s

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