Update im-rc requirement from 12.1.0 to 13.0.0

[dependabot-preview]

Updates the requirements on im-rc to permit the latest version.

Release notes

Sourced from im-rc's releases.

13.0.0

The minimum supported Rust version is now 1.34.0.

Changed

• im::iter::unfold now gives you the owned state value rather than an immutable reference to it, which makes it a little more useful.

Removed

• The deprecated singleton constructors have been removed. Please use unit instead.
• The deprecated methods Vector::chunks and Vector::chunks_mut have been removed in favour of Vector::leaves and Vector::leaves_mut respectively. (#50)
• The deprecated reference to sized-chunks has been removed. If you need it, please use the sized-chunks crate directly.
• im::iter::unfold_mut has been removed, as there's no meaningful difference between it and rust-std 1.34.0's std::iter::from_fn with a captured state variable.

Fixed

• Vector now uses sized_chunks::InlineArray instead of an Empty enum case to avoid allocation at very small sizes, letting you store a handful of elements on the stack before needing to grow into a full chunk. This has a beneficial effect on performance as well, as there's no pointer into the heap to dereference, making it faster than std::vec::Vec in this configuration.
• Some complexity timings have been added and corrected. (#87)
• OrdSet::is_subset(&self, other) now returns immediately when self is larger than other and thus could not possibly be a subset of it. (#87)

Changelog

Sourced from im-rc's changelog.

[13.0.0] - 2019-05-18

The minimum supported Rust version is now 1.34.0.

Changed

• im::iter::unfold now gives you the owned state value rather than an
  immutable reference to it, which makes it a little more useful.

Removed

• The deprecated singleton constructors have been removed. Please use unit
  instead.
• The deprecated methods Vector::chunks and Vector::chunks_mut have been
  removed in favour of Vector::leaves and Vector::leaves_mut respectively.
  (#50)
• The deprecated reference to sized-chunks
  has been removed. If you need it, please use the sized-chunks crate directly.
• im::iter::unfold_mut has been removed, as there's no meaningful difference
  between it and rust-std 1.34.0's std::iter::from_fn with a captured state
  variable.

Fixed

• Vector now uses
  sized_chunks::InlineArray
  instead of an Empty enum case to avoid allocation at very small sizes,
  letting you store a handful of elements on the stack before needing to grow
  into a full chunk. This has a beneficial effect on performance as well, as
  there's no pointer into the heap to dereference, making it faster than
  std::vec::Vec in this configuration.
• Some complexity timings have been added and corrected. (#87)
• OrdSet::is_subset(&self, other) now returns immediately when self is
  larger than other and thus could not possibly be a subset of it. (#87)

[12.3.4] - 2019-04-08

Changed

• Clone constraints have been further relaxed on maps and sets, so that you
  can now lookup and iterate over them without requiring a Clone constraint
  (though you do still need Clone to actually insert data into them to lookup
  or iterate over). (#81)

Fixed

• Enforces the latest bugfix release of sized-chunks. (#78)
• Another edge case bugfix to Vector's size table handling. (#79)

[12.3.3] - 2019-03-11

... (truncated)

Commits

• 1e59b66 (cargo-release) version 13.0.0
• 6ddf406 Broken link fix.
• 60de96d Replace Vector::Empty with Vector::Inline using InlineArray.
• b7578f8 Fix Vector benchmark from_fn issues.
• d2befa1 Merge pull request #89 from AljoschaMeyer/master
• f519c66 Adjust doc tests
• 37f8046 Add relative_complement to sets/maps
• 01f2726 Add symmetrical_difference to sets/maps
• c0a8fc6 Add timings to more OrdSet ops, and an early return optimisation to `is_sub...
• 7c5f501 Merge pull request #84 from bodil/dependabot/cargo/sized-chunks-0.2.0
• Additional commits viewable in compare view

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[alexcrichton]

@bors: r+

[bors]

📌 Commit 966e7f9 has been approved by alexcrichton

[bors]

⌛ Testing commit 966e7f9 with merge 00e4c69...

[bors]

☀️ Test successful - checks-travis, status-appveyor
Approved by: alexcrichton
Pushing 00e4c69 to master...