ci: bump overall MSRV to fix failure

the `glib` crate has bumped their MSRV to 1.56 so we must do likewise for
the overall workspace MSRV to fix the CI failure related to this.

Author: jnqnfe

.github/workflows/test.yml

@@ -25,7 +25,7 @@ jobs:
         # Use the Ubuntu Focal (20.04) environment, which uses PA v13.99.1
         os: [ubuntu-20.04]
         rustc:
-          - 1.53.0 # Overall MSRV (Minimum supported rust version)
+          - 1.56.0 # Overall MSRV (Minimum supported rust version)
           - stable
           - beta
         # Allow failure?

pulse-binding-mainloop-glib/README.md

@@ -4,7 +4,7 @@ libpulse-glib-binding
 [<img alt="GitHub Workflow Status" src="https://img.shields.io/github/workflow/status/jnqnfe/pulse-binding-rust/Build%20&%20Test/master?style=for-the-badge" height="24">](https://github.com/jnqnfe/pulse-binding-rust/actions)
 [<img alt="crates.io" src="https://img.shields.io/crates/v/libpulse-glib-binding?style=for-the-badge" height="24">](https://crates.io/crates/libpulse-glib-binding)
 [<img alt="docs.rs" src="https://img.shields.io/crates/v/libpulse-glib-binding?color=5479ab&label=docs.rs&style=for-the-badge" height="24">](https://docs.rs/libpulse-glib-binding)
-[<img alt="min-rust-version" src="https://img.shields.io/static/v1?label=RUST&message=1.53%2B&color=informational&style=for-the-badge" height="24">](https://rust-lang.github.io/rfcs/2495-min-rust-version.html)
+[<img alt="min-rust-version" src="https://img.shields.io/static/v1?label=RUST&message=1.56%2B&color=informational&style=for-the-badge" height="24">](https://rust-lang.github.io/rfcs/2495-min-rust-version.html)
 
 A Rust language binding for the PulseAudio libpulse-mainloop-glib library.
 

pulse-sys-mainloop-glib/README.md

@@ -4,7 +4,7 @@ libpulse-mainloop-glib-sys
 [<img alt="GitHub Workflow Status" src="https://img.shields.io/github/workflow/status/jnqnfe/pulse-binding-rust/Build%20&%20Test/master?style=for-the-badge" height="24">](https://github.com/jnqnfe/pulse-binding-rust/actions)
 [<img alt="crates.io" src="https://img.shields.io/crates/v/libpulse-mainloop-glib-sys?style=for-the-badge" height="24">](https://crates.io/crates/libpulse-mainloop-glib-sys)
 [<img alt="docs.rs" src="https://img.shields.io/crates/v/libpulse-mainloop-glib-sys?color=5479ab&label=docs.rs&style=for-the-badge" height="24">](https://docs.rs/libpulse-mainloop-glib-sys)
-[<img alt="min-rust-version" src="https://img.shields.io/static/v1?label=RUST&message=1.53%2B&color=informational&style=for-the-badge" height="24">](https://rust-lang.github.io/rfcs/2495-min-rust-version.html)
+[<img alt="min-rust-version" src="https://img.shields.io/static/v1?label=RUST&message=1.56%2B&color=informational&style=for-the-badge" height="24">](https://rust-lang.github.io/rfcs/2495-min-rust-version.html)
 
 FFI bindings for the PulseAudio libpulse-mainloop-glib system library. See also the higher-level
 [`libpulse-glib-binding`](https://crates.io/crates/libpulse-glib-binding) crate.