Update cachetools requirement from <5,>=4 to >=4,<6

[dependabot]

Updates the requirements on cachetools to permit the latest version.

Changelog

Sourced from cachetools's changelog.

v5.0.0 (2021-12-21)

• Require Python 3.7 or later (breaking change).

• Remove deprecated submodules (breaking change).

  The cache, fifo, lfu, lru, mru, rr and ttl submodules have been deleted. Therefore, statements like

  from cachetools.ttl import TTLCache

  will no longer work. Use

  from cachetools import TTLCache

  instead.

• Pass self to @cachedmethod key function (breaking change).

  The key function passed to the @cachedmethod decorator is now called as key(self, *args, **kwargs).

  The default key function has been changed to ignore its first argument, so this should only affect applications using custom key functions with the @cachedmethod decorator.

• Change exact time of expiration in TTLCache (breaking change).

  TTLCache items now get expired if their expiration time is less than or equal to timer(). For applications using the default timer(), this should be barely noticable, but it may affect the use of custom timers with larger tick intervals. Note that this also implies that a TTLCache with ttl=0 can no longer hold any items, since they will expire immediately.

• Change Cache.__repr__() format (breaking change).

  String representations of cache instances now use a more compact and efficient format, e.g.

  LRUCache({1: 1, 2: 2}, maxsize=10, currsize=2)

• Add TLRU cache implementation.

• Documentation improvements.

v4.2.4 (2021-09-30)

... (truncated)

Commits

• f8a166b Release v5.0.0.
• 53b9b77 Prepare v5.0.0.
• 749a2c5 Fix #159: Pass self to @​cachedmethod key function.
• d4b1569 Refactor time aware caches.
• 9b731f5 Fix #157: Add TLRU cache implementation.
• f949504 Fix #169: Improve getsizeof() documentation.
• fce151a Fix #233: Drop support for Python 3.5 and 3.6.
• ad93a2f Fix #221: Change exact time of expiration in TTLCache.
• 99e001a Fix #227: Change Cache.repr() format.
• 33073cb Remove deprecated submodules.
• Additional commits viewable in compare view

Dependabot will resolve any conflicts with this PR as long as you don't alter it yourself. You can also trigger a rebase manually by commenting @dependabot rebase.

---

Dependabot commands and options

You can trigger Dependabot actions by commenting on this PR:

• @dependabot rebase will rebase this PR
• @dependabot recreate will recreate this PR, overwriting any edits that have been made to it
• @dependabot merge will merge this PR after your CI passes on it
• @dependabot squash and merge will squash and merge this PR after your CI passes on it
• @dependabot cancel merge will cancel a previously requested merge and block automerging
• @dependabot reopen will reopen this PR if it is closed
• @dependabot close will close this PR and stop Dependabot recreating it. You can achieve the same result by closing it manually
• @dependabot ignore this major version will close this PR and stop Dependabot creating any more for this major version (unless you reopen the PR or upgrade to it yourself)
• @dependabot ignore this minor version will close this PR and stop Dependabot creating any more for this minor version (unless you reopen the PR or upgrade to it yourself)
• @dependabot ignore this dependency will close this PR and stop Dependabot creating any more for this dependency (unless you reopen the PR or upgrade to it yourself)

[codecov]

Codecov Report

Merging #1987 (404d9d8) into latest (0119cf7) will increase coverage by 7.90%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           latest    #1987      +/-   ##
==========================================
+ Coverage   83.53%   91.43%   +7.90%     
==========================================
  Files         127       96      -31     
  Lines       14233     9953    -4280     
  Branches     1946     1946              
==========================================
- Hits        11890     9101    -2789     
+ Misses       2070      579    -1491     
  Partials      273      273              

Flag	Coverage Δ
python	91.43% <ø> (ø)
rust	?

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
src/core/tests/storage.rs
src/core/src/index/bigsi.rs
src/core/src/index/revindex.rs
src/core/src/storage.rs
src/core/src/ffi/utils.rs
src/core/src/index/sbt/mhbt.rs
src/core/src/from.rs
src/core/src/cmd.rs
src/core/src/errors.rs
src/core/src/index/sbt/mod.rs
... and 21 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 0119cf7...404d9d8. Read the comment docs.