Fix MSRV in README and CHANGELOG

Author: rafalh

CHANGELOG.md

@@ -30,7 +30,7 @@ New features:
 * Fix `format_volume` function panicking in debug build for FAT12 volumes with size below 1 MB
 * Fix index out of range panic when reading 248+ characters long file names with `alloc` feature disabled
 * Remove `byteorder` dependency.
-* Bump up minimal Rust compiler version to 1.46.0.
+* Bump up minimal Rust compiler version to 1.48.0.
 * Build the crate using the 2018 edition.
 * Add support for compile-time configuration of logging levels via Cargo features. By default, all logging levels are
   enabled, including "trace" and up.

README.md

@@ -5,7 +5,7 @@ Rust FAT FS
 [![MIT licensed](https://img.shields.io/badge/license-MIT-blue.svg)](./LICENSE.txt)
 [![crates.io](https://img.shields.io/crates/v/fatfs)](https://crates.io/crates/fatfs)
 [![Documentation](https://docs.rs/fatfs/badge.svg)](https://docs.rs/fatfs)
-[![Minimum rustc version](https://img.shields.io/badge/rustc-1.46+-yellow.svg)](https://blog.rust-lang.org/2020/08/27/Rust-1.46.0.html)
+[![Minimum rustc version](https://img.shields.io/badge/rustc-1.48+-yellow.svg)](https://blog.rust-lang.org/2020/11/19/Rust-1.48.html)
 
 A FAT filesystem library implemented in Rust.