Minor release: v2.8

[geky]

This release brings in some useful community-driven features. Thanks everyone who has put up PRs!

Bringing in:

• https://github.com/littlefs-project/littlefs/pull/866
• https://github.com/littlefs-project/littlefs/pull/872
• https://github.com/littlefs-project/littlefs/pull/875

Draft of release notes follows:

---

This release brings in some useful community-driven features.

What's new?

• Thanks to @BrianPugh, littlefs no longer needs the block_count when mounting an existing filesystem (#866)

  Simply set block_count=0 in your configuration, and littlefs will automatically determine the block_count based on what's on disk. This allows you to mount a filesystem of unknown size.

• Added lfs_fs_grow which allows you to change the size of an existing filesystem, thanks to @kaetemi (#872)

  The main use case is for changing the size of a partition as storage requirements change.

  Note: littlefs does not support shrinking a filesystem, and this is unlikely to change (it's a hard problem).

• Added lfs_fs_gc which allows you to manually run the block allocator, thanks to @opilat (#875)

  Note: littlefs currently does not persist any found free blocks to disk, though this may change in the future.

  This limits the current value of lfs_fs_gc, but it may still be useful for moving the expensive block scan out of performance sensitive code paths.

[geky-bot]

Tests passed ✓, Code: 16838 B (+1.0%), Stack: 1448 B (+1.1%), Structs: 800 B (+1.5%)

| | Code | Stack | Structs | | Coverage | |:--|-----:|------:|--------:|:--|---------:| | Default | 16838 B (+1.0%) | 1448 B (+1.1%) | 800 B (+1.5%) | Lines | 2357/2533 lines (+0.3%) | | Readonly | 6130 B (+0.1%) | 448 B (+0.0%) | 800 B (+1.5%) | Branches | 1202/1528 branches (+0.1%) | | Threadsafe | 17722 B (+1.2%) | 1448 B (+1.1%) | 808 B (+1.5%) | | **Benchmarks** | | Multiversion | 16898 B (+0.9%) | 1448 B (+1.1%) | 804 B (+1.5%) | Readed | 29369693876 B (+0.0%) | | Migrate | 18514 B (+0.8%) | 1752 B (+0.9%) | 804 B (+1.5%) | Proged | 1482874766 B (+0.0%) | | Error-asserts | 17498 B (+1.1%) | 1440 B (+1.1%) | 800 B (+1.5%) | Erased | 1568888832 B (+0.0%) |