Update futures requirement from 0.1.12 to 0.3.5

[dependabot-preview]

Updates the requirements on futures to permit the latest version.

Release notes

Sourced from futures's releases.

0.3.5

• Added StreamExt::flat_map.
• Added StreamExt::ready_chunks.
• Added *_unpin methods to SinkExt.
• Added a cancellation() future to oneshot::Sender.
• Added reunite method to ReadHalf and WriteHalf.
• Added Extend implementations for Futures(Un)Ordered and SelectAll.
• Added support for reexporting the join! and select! macros.
• Added no_std support for the pending! and poll! macros.
• Added Send and Sync support for AssertUnmoved.
• Fixed a bug where Shared wasn't relinquishing control to the executor.
• Removed the Send bound on the output of RemoteHandle.
• Relaxed bounds on FuturesUnordered.
• Reorganized internal tests to work under different --features.
• Reorganized the bounds on StreamExt::forward.
• Removed and replaced a large amount of internal unsafe.

Changelog

Sourced from futures's changelog.

0.3.5 - 2020-05-08

• Added StreamExt::flat_map.
• Added StreamExt::ready_chunks.
• Added *_unpin methods to SinkExt.
• Added a cancellation() future to oneshot::Sender.
• Added reunite method to ReadHalf and WriteHalf.
• Added Extend implementations for Futures(Un)Ordered and SelectAll.
• Added support for reexporting the join! and select! macros.
• Added no_std support for the pending! and poll! macros.
• Added Send and Sync support for AssertUnmoved.
• Fixed a bug where Shared wasn't relinquishing control to the executor.
• Removed the Send bound on the output of RemoteHandle.
• Relaxed bounds on FuturesUnordered.
• Reorganized internal tests to work under different --features.
• Reorganized the bounds on StreamExt::forward.
• Removed and replaced a large amount of internal unsafe.

0.3.4 - 2020-02-06

• Fixed missing Drop for UnboundedReceiver (#2064)

0.3.3 - 2020-02-04

• Fixed compatibility issue with pinned facade (#2062)

0.3.2 - 2020-02-03

• Improved buffering performance of SplitSink (#1969)
• Added select_biased! macro (#1976)
• Added hash_receiver method to mpsc channel (#1962)
• Added stream::try_unfold (#1977)
• Fixed bug with zero-size buffers in vectored IO (#1998)
• AtomicWaker::new() is now const fn (#2007)
• Fixed bug between threadpool and user park/unparking (#2010)
• Added stream::Peakable::peek (#2021)
• Added StreamExt::scan (#2044)
• Added impl of AsyncRead/Write for BufReader/Writer (#2033)
• Added impl of Spawn and LocalSpawn for Arc<impl Spawn and Rc<impl Spawn> (#2039)
• Fixed Sync issues with FuturesUnordered (#2054)
• Added into_inner method for future::Ready (#2055)
• Added MappedMutexGuard API (#2056)
• Mitigated starvation issues in FuturesUnordered (#2049)
• Added TryFutureExt::map_ok_or_else (#2058)

0.3.1 - 2019-11-7

• Fix signature of LocalSpawn trait (breaking change -- see #1959)

0.3.0 - 2019-11-5

• Stable release along with stable async/await!
• Added async/await to default features (#1953)
• Changed Spawn trait and FuturesUnordered::push to take &self (#1950)
• Moved Spawn and FutureObj out of futures-core and into futures-task (#1925)
• Changed case convention for feature names (#1937)

... (truncated)

Commits

• 4ceafb3 Stage 0.3.5
• 5b91728 Drop unneeded Send/Sync bound from AssertUnmoved
• 4b930bb Implement Send + Sync for AssertUnmoved
• 3bf5ac9 Merge pull request #2128 from Diggsey/snip
• 1b44548 Merge branch 'master' into snip
• 32005e3 fix: Shared must relinquish control to the executor if repolled
• dc06eda Update pin-utils to 0.1
• dc00793 Make ready and lazy's panic messages easy to understand
• 127b244 Allow pending! and poll! in no_std
• dfc6673 Update futures-util/src/future/future/flatten.rs
• Additional commits viewable in compare view

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