Update pinned ci version

azure-pipelines.yml

@@ -21,7 +21,7 @@ stages:
               rustup_toolchain: stable
             linux-pinned:
               imageName: 'ubuntu-20.04'
-              rustup_toolchain: 1.49.0
+              rustup_toolchain: 1.51.0
         pool:
           vmImage: $(imageName)
         steps:

docs/content/documentation/getting-started/installation.md

@@ -130,7 +130,7 @@ $ choco install zola
 Zola does not work in PowerShell ISE.
 
 ## From source
-To build Zola from source, you will need to have Git, [Rust (at least 1.49) and Cargo](https://www.rust-lang.org/)
+To build Zola from source, you will need to have Git, [Rust and Cargo](https://www.rust-lang.org/)
 installed. You will also need to meet additional dependencies to compile [libsass](https://github.com/sass/libsass):
 
 - OSX, Linux and other Unix-like operating systems: `make` (`gmake` on BSDs), `g++`, `libssl-dev`