docs: fix typo (#142)

"it's" with an apostrophe is a contraction of "it is" or "it has", and "its" without an apostrophe is the possessive form of "it". It should be "on its own" since the intended meaning is not "on it is own".

miniz_oxide/Readme.md

@@ -1,7 +1,7 @@
 # miniz_oxide
 
 A fully safe, pure rust replacement for the [miniz](https://github.com/richgel999/miniz) DEFLATE/zlib encoder/decoder.
-The main intention of this crate is to be used as a back-end for the [flate2](https://github.com/alexcrichton/flate2-rs), but it can also be used on it's own. Using flate2 with the ```rust_backend``` feature provides an easy to use streaming API for miniz_oxide.
+The main intention of this crate is to be used as a back-end for the [flate2](https://github.com/alexcrichton/flate2-rs), but it can also be used on its own. Using flate2 with the ```rust_backend``` feature provides an easy to use streaming API for miniz_oxide.
 
 The library is fully [no_std](https://docs.rust-embedded.org/book/intro/no-std.html). By default, the `with-alloc` feature is enabled, which requires the use of the `alloc` and `collection` crates as it allocates memory.